How not to replace email: lessons from Google Wave
Wave was cool technology with interesting ideas, but there is no substitute for getting the user interface right, and unfortunately they didn't. It's been a long time and there might be others I'm forgetting, but there were two important design errors:1. Email lets you type an entire message before sending; IRC at least lets you type a whole paragraph, which is enough. Wave didn't let you type more than one character before sending.2. The designers correctly realized chronological order isn't enough, you also want logical order, but unfortunately they provided the latter instead of the former, whereas you actually need both. (Gmail provides both: new messages and threads. Git provides both: view changes, and view current code. Google Docs provides both. Either view alone does not suffice.)I would by all means encourage someone to take another shot at building something like Wave, with those problems fixed.