That makes sense and I think my comment was a little ambiguous. It wasn't so much an endorsement of cryptocat itself, but the idea that using a centralized system that supports encryption may be a reasonable compromise to protect against indiscriminate collection by third parties, and something I think existing companies that handle most communication already could generally implement.
For instance, OTR (as implemented by IM clients) is an example of an extraordinarily simple cryptosystem (I'd argue too simple) that at least provides for a notion of persistent keys.