With over 12 million entities and 350 million relationships, Freebase is an excellent resource for performing text analysis. One way to look at document "understanding" is to think about how the entities in the document are connected on a knowledge graph. This is similar to the "reconciliation" process that is used to grow Freebase itself.
The web is currently full of semantic hints, whether they are explicit (like those promoted by the Semantic Web) or implicit (like the use of blog widgets.) Using these hints, text analytic methods can get a toe-hold on the web corpus at large.