Add documentaion about scopes (issue
Crawling Strategies
###################
+ACHE has several configuration options to control the crawling strategy, i.e.,
+which links the crawler should follow and priority of each link.
+
Scope
-----
-TODO
+Scope refers to the ability of the crawler only follow links that point to the
+same "host". If the crawler is configured to use the "seed scope", it will only
+follow links that belong to the same host of the URLs included in the seeds
+file. You can enable scope adding the following line to ``ache.yml``:
+
+.. code:: yaml
+
+ link_storage.link_strategy.use_scope: true
+
+For example, if the scope is enabled and the seed file contains the following
+URLs::
+
+ http://pt.wikipedia.org/
+ http://en.wikipedia.org/
+
+then the crawler will only follow links within the domains ``pt.wikipedia.org``
+and ``en.wikipedia.org``. Links to any other domains will be ignored.
Hard-focus vs. Soft-focus
-------------------------
TODO
-
Link Classifiers
----------------
TODO
