diff --git a/.gitignore b/.gitignore
index c731916..da70ff2 100644
--- a/.gitignore
+++ b/.gitignore
@@ -9,6 +9,7 @@
 *.py[cod]
 *.so
 *.spec
+.*.sw?
 .Python
 .cache
 .coverage
diff --git a/Makefile b/Makefile
index c580632..e84f7a5 100644
--- a/Makefile
+++ b/Makefile
@@ -1,7 +1,7 @@
 # This file has been auto-generated.
 # All changes will be lost, see Projectfile.
 #
-# Updated at 2016-12-28 15:50:31.026587
+# Updated at 2016-12-29 17:04:15.403353
 
 PYTHON ?= $(shell which python)
 PYTHON_BASENAME ?= $(shell basename $(PYTHON))
diff --git a/bonobo/__init__.py b/bonobo/__init__.py
index d70e30a..685e08d 100644
--- a/bonobo/__init__.py
+++ b/bonobo/__init__.py
@@ -19,21 +19,15 @@
     See the License for the specific language governing permissions and
     limitations under the License.
 """
-import os
 import sys
 
+assert (sys.version_info >= (3, 5)), 'Python 3.5+ is required to use Bonobo.'
+
+from ._version import __version__
 from .core import *
 from .io import CsvReader, CsvWriter, FileReader, FileWriter, JsonReader, JsonWriter
 from .util import *
 
-PY35 = (sys.version_info >= (3, 5))
-
-assert PY35, 'Python 3.5+ is required to use Bonobo.'
-
-# Version infos
-with open(os.path.realpath(os.path.join(os.path.dirname(__file__), '../version.txt'))) as f:
-    __version__ = f.read().strip()
-
 __all__ = [
     'Bag',
     'CsvReader',
@@ -47,6 +41,7 @@ __all__ = [
     'NaiveStrategy',
     'ProcessPoolExecutorStrategy',
     'ThreadPoolExecutorStrategy',
+    '__version__',
     'console_run',
     'head',
     'inject',
diff --git a/bonobo/_version.py b/bonobo/_version.py
new file mode 100644
index 0000000..8ce9b36
--- /dev/null
+++ b/bonobo/_version.py
@@ -0,0 +1 @@
+__version__ = '0.1.3'
diff --git a/docs/_static/custom.css b/docs/_static/custom.css
new file mode 100644
index 0000000..f658da9
--- /dev/null
+++ b/docs/_static/custom.css
@@ -0,0 +1,3 @@
+svg {
+    border: 2px solid green
+}
\ No newline at end of file
diff --git a/docs/_static/graphs.css b/docs/_static/graphs.css
new file mode 100644
index 0000000..873f3d6
--- /dev/null
+++ b/docs/_static/graphs.css
@@ -0,0 +1,2 @@
+.node {
+}
\ No newline at end of file
diff --git a/docs/guide/crawlers.rst b/docs/guide/crawlers.rst
new file mode 100644
index 0000000..7a9a181
--- /dev/null
+++ b/docs/guide/crawlers.rst
@@ -0,0 +1,33 @@
+Web crawlers with Bonobo
+========================
+
+.. todo:: Bonobo-Selenium is at a very alpha stage, and things will change. This section is here to give a brief
+          overview but is neither complete nor definitive.
+
+Writing web crawlers with Bonobo and Selenium is easy.
+
+First, install **bonobo-selenium**:
+
+.. code-block:: shell-session
+
+    $ pip install bonobo-selenium
+
+The idea is to have one callable crawl one thing and delegate drill downs to callables further away in the chain.
+
+An example chain could be:
+
+.. graphviz::
+
+    digraph {
+        rankdir = LR;
+        login -> paginate -> list -> details -> "ExcelWriter(...)";
+    }
+
+Where each step would do the following:
+
+* `login()` is in charge to open an authenticated session in the browser.
+* `paginate()` open each page of a fictive list and pass it to next.
+* `list()` take every list item and yield it.
+* `details()` extract the data you're interested in.
+* ... and the writer saves it somewhere.
+
diff --git a/docs/guide/index.rst b/docs/guide/index.rst
index ebd0d17..99ae56f 100644
--- a/docs/guide/index.rst
+++ b/docs/guide/index.rst
@@ -1,4 +1,8 @@
 Guides
 ======
 
-.. todo:: write the fucking doc!
+.. toctree::
+    :maxdepth: 2
+
+    purity
+    crawlers
diff --git a/docs/guide/purity.rst b/docs/guide/purity.rst
new file mode 100644
index 0000000..1995284
--- /dev/null
+++ b/docs/guide/purity.rst
@@ -0,0 +1,128 @@
+Pure components and space complexity
+====================================
+
+The nature of components, and how the data flow from one to another, make them not so easy to write correctly.
+Hopefully, with a few hints, you will be able to understand why and how they should be written.
+
+The major problem we have is that one message can go through more than one component, and at the same time. If you
+wanna be safe, you tend to :func:`copy.copy()` everything between two calls to two different components, but that
+will mean that a lot of useless memory space would be taken for copies that are never modified.
+
+Instead of that, we chosed the oposite: copies are never made, and you should not modify in place the inputs of your
+component before yielding them, and that mostly means that you want to recreate dicts and lists before yielding (or
+returning) them. Numeric values, strings and tuples being immutable in python, modifying a variable of one of those
+type will already return a different instance.
+
+Numbers
+=======
+
+You can't be wrong with numbers. All of the following are correct.
+
+.. code-block:: python
+
+    def do_your_number_thing(n: int) -> int:
+        return n
+
+    def do_your_number_thing(n: int) -> int:
+        yield n
+
+    def do_your_number_thing(n: int) -> int:
+        return n + 1
+
+    def do_your_number_thing(n: int) -> int:
+        yield n + 1
+
+    def do_your_number_thing(n: int) -> int:
+        # correct, but bad style
+        n += 1
+        return n
+
+    def do_your_number_thing(n: int) -> int:
+        # correct, but bad style
+        n += 1
+        yield n
+
+The same is true with other numeric types, so don't be shy. Operate like crazy, my friend.
+
+Tuples
+======
+
+Tuples are immutable, so you risk nothing.
+
+.. code-block:: python
+
+    def do_your_tuple_thing(t: tuple) -> tuple:
+        return ('foo', ) + t
+
+    def do_your_tuple_thing(t: tuple) -> tuple:
+        return t + ('bar', )
+
+    def do_your_tuple_thing(t: tuple) -> tuple:
+        # correct, but bad style
+        t += ('baaaz', )
+        return t
+
+Strings
+=======
+
+You know the drill, strings are immutable, blablabla ... Examples left as an exercise for the reader.
+
+Dicts
+=====
+
+So, now it gets interesting. Dicts are mutable. It means that you can mess things up badly here if you're not cautious.
+
+For example, doing the following may cause unexpected problems:
+
+.. code-block:: python
+
+    def mutate_my_dict_like_crazy(d: dict) -> dict:
+        # Bad! Don't do that!
+        d.update({
+            'foo': compute_something()
+        })
+        # Still bad! Don't mutate the dict!
+        d['bar']: compute_anotherthing()
+        return d
+
+The problem is easy to understand: as **Bonobo** won't make copies of your dict, the same dict will be passed along the
+transformation graph, and mutations will be seen in components downwards the output, but also upward. Let's see
+a more obvious example of something you should not do:
+
+.. code-block:: python
+
+    def mutate_my_dict_and_yield() -> dict:
+        d = {}
+        for i in range(100):
+            # Bad! Don't do that!
+            d['index'] = i
+            yield d
+
+Here, the same dict is yielded in each iteration, and its state when the next component in chain is called is undetermined.
+
+Now let's see how to do it correctly:
+
+.. code-block:: python
+
+    def new_dicts_like_crazy(d: dict) -> dict:
+        # Creating a new dict is correct.
+        return {
+            **d,
+            'foo': compute_something(),
+            'bar': compute_anotherthing(),
+        }
+
+    def new_dict_and_yield() -> dict:
+        d = {}
+        for i in range(100):
+            # Different dict each time.
+            yield {
+                'index': i
+            }
+
+I hear you think «Yeah, but if I create like millions of dicts ...». The answer is simple. Using dicts like this will
+create a lot, but also free a lot because as soon as all the future components that take this dict as input are done,
+the dict will be garbage collected. Youplaboum!
+
+
+
diff --git a/docs/reference/bonobo.ext.console.rst b/docs/reference/bonobo.ext.console.rst
deleted file mode 100644
index 4385466..0000000
--- a/docs/reference/bonobo.ext.console.rst
+++ /dev/null
@@ -1,22 +0,0 @@
-bonobo.ext.console package
-==========================
-
-Submodules
-----------
-
-bonobo.ext.console.plugin module
---------------------------------
-
-.. automodule:: bonobo.ext.console.plugin
-    :members:
-    :undoc-members:
-    :show-inheritance:
-
-
-Module contents
----------------
-
-.. automodule:: bonobo.ext.console
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/reference/bonobo.ext.jupyter.rst b/docs/reference/bonobo.ext.jupyter.rst
deleted file mode 100644
index c695678..0000000
--- a/docs/reference/bonobo.ext.jupyter.rst
+++ /dev/null
@@ -1,30 +0,0 @@
-bonobo.ext.jupyter package
-==========================
-
-Submodules
-----------
-
-bonobo.ext.jupyter.plugin module
---------------------------------
-
-.. automodule:: bonobo.ext.jupyter.plugin
-    :members:
-    :undoc-members:
-    :show-inheritance:
-
-bonobo.ext.jupyter.widget module
---------------------------------
-
-.. automodule:: bonobo.ext.jupyter.widget
-    :members:
-    :undoc-members:
-    :show-inheritance:
-
-
-Module contents
----------------
-
-.. automodule:: bonobo.ext.jupyter
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/reference/bonobo.ext.rst b/docs/reference/bonobo.ext.rst
deleted file mode 100644
index 63327ef..0000000
--- a/docs/reference/bonobo.ext.rst
+++ /dev/null
@@ -1,46 +0,0 @@
-bonobo.ext package
-==================
-
-Subpackages
------------
-
-.. toctree::
-
-    bonobo.ext.console
-    bonobo.ext.jupyter
-
-Submodules
-----------
-
-bonobo.ext.couchdb_ module
---------------------------
-
-.. automodule:: bonobo.ext.couchdb_
-    :members:
-    :undoc-members:
-    :show-inheritance:
-
-bonobo.ext.opendatasoft module
-------------------------------
-
-.. automodule:: bonobo.ext.opendatasoft
-    :members:
-    :undoc-members:
-    :show-inheritance:
-
-bonobo.ext.selenium module
---------------------------
-
-.. automodule:: bonobo.ext.selenium
-    :members:
-    :undoc-members:
-    :show-inheritance:
-
-
-Module contents
----------------
-
-.. automodule:: bonobo.ext
-    :members:
-    :undoc-members:
-    :show-inheritance:
diff --git a/docs/tutorial/basics.rst b/docs/tutorial/basics.rst
index ad507b7..3b1b989 100644
--- a/docs/tutorial/basics.rst
+++ b/docs/tutorial/basics.rst
@@ -58,7 +58,10 @@ Let's chain the three components together and run the transformation:
 
     digraph {
         rankdir = LR;
-        "generate_data" -> "uppercase" -> "output";
+        stylesheet = "../_static/graphs.css";
+
+        BEGIN [shape="point"];
+        BEGIN -> "generate_data" -> "uppercase" -> "output";
     }
 
 We use the :func:`bonobo.run` helper that hides the underlying object composition necessary to actually run the
diff --git a/setup.py b/setup.py
index 624fd3f..a19e5bd 100644
--- a/setup.py
+++ b/setup.py
@@ -1,8 +1,11 @@
 # This file is autogenerated by edgy.project code generator.
 # All changes will be overwritten.
 
+import os
 from setuptools import setup, find_packages
 
+root_dir = os.path.dirname(os.path.abspath(__file__))
+
 tolines = lambda c: list(filter(None, map(lambda s: s.strip(), c.split('\n'))))
 
 
@@ -12,10 +15,19 @@ def read(filename, flt=None):
         return flt(content) if callable(flt) else content
 
 
+# Py3 compatibility hacks, borrowed from IPython.
 try:
-    version = read('version.txt')
-except:  # pylint: disable=bare-except
-    version = 'dev'
+    execfile
+except NameError:
+
+    def execfile(fname, globs, locs=None):
+        locs = locs or globs
+        exec(compile(open(fname).read(), fname, "exec"), globs, locs)
+
+
+version_ns = {}
+execfile(os.path.join(root_dir, 'bonobo/_version.py'), version_ns)
+version = version_ns.get('__version__', 'dev')
 
 setup(
     name='bonobo',
diff --git a/version.txt b/version.txt
deleted file mode 100644
index d917d3e..0000000
--- a/version.txt
+++ /dev/null
@@ -1 +0,0 @@
-0.1.2