I agree, context is important, and humans are better at separating context if it's "physically" separated, eg. a different site or window. However, if you look

I agree, context is important, and humans are better at separating context if it's "physically" separated, eg. a different site or window. However, if you look at the Gmail+Gtalk use-case, the fact that all conversations that go through Google's Jabber servers are automatically indexed and searchable in Gmail alone is a killer feature (this also works if you use a desktop client like Adium, the point is, it makes sense to use Google as your IM provider for the indexing). So the point is, keeping as many docs/conversations/etc in some centralized Google app may be worth it just for the search/indexing. My final conclusion then is that other companies, in the long term, may have to implement Google-like search functionality (and storage), otherwise Google will suck up their application's users with search as a killer feature.