I have an application for sending out say around 100+ tweets every day. I am using OAuth for authentication. The twitter API says that post messages are not rate limited. Ho
Are you using some kind of shared hosting? the twitter API is limited by IP address and if there are other apps on your IP address also using the twitter API then you will be sharing rate limits with them. I ran into this issue with a tiny app on google app engine, despite only making about 10 requests in an hour.