In Jeff's recent Q&A, listen to his answer to a question about searching chat logs (37:53). We tested Slack internally and his point about searching paragraphs vs. sentences or words is exactly right. The trouble I had with Slack is that without replies, it's impossible to piece together a conversation.

Want to make a new user feel really awful about posting a question? Have an entire conversation about them, and how "new users don't do research" with someone else in comments, in plain view of the user, as if they weren't even there.