I Tweet most often about one of three things: 1. Links to other pages with my commentary, which may either be my own material or something else I've found interesting. 2. Ideas I'm floating. Don't be ashamed to float funky ideas. People may trash you for it, but they'll forget about it before long, in most cases, and you'll get an unbiased sense of the viability of the idea. 3. Conversation with other people. Why put this third? Because while it's important, if you're holding a conversation, others not a party to that conversation won't have any idea what you're talking about. You have a responsibility to your Twitter followers to put out interesting ideas, and if someone is out of the loop, you've failed at that. So have the conversations, but don't let that dominate your dialogue.