How can you expect anyone to follow you if they're asleep? Sending messages, or twittering, during peak hours gives you the best opportunity to be seen, or, rather, read. And that gives you better odds of someone enjoying whatever messages you're sending out and signing up as a follower. So what are the peak hours? There haven't been any studies performed yet, but the Washington, D.C.-based Internet marketing firm Abraham & Harrison have performed some Webinars along with Twitter and confirmed that 9 a.m., noon, 3 p.m. and 6 p.m. see heavy use. It's also an opportunity for you to experiment with your tweets and see when you're getting the best response. If you do find that between 9 a.m. and 6 p.m. in the United States, either East or West Coast time, gets you a lot of traffic and you live elsewhere in the world, structure you tweets around this schedule. It may not be the most convenient time for you, but if you're interested in gaining followers, you need to be around when the bulk of Twitter users are around.