+
+> I've implemented influence calculation in `add_depends`. As expected,
+> it means rather a lot more work, and makes some things much slower.
+> Optimisation via `pagespec_match_depends` next.. --[[Joey]]
+
+#### Influence types
+
+Note that influences can also have types, same as dependency types.
+For example, "backlink(foo)" has an influence of foo, of type links.
+"created_before(foo)" also is influenced by foo, but it's a presence
+type. Etc.