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
Yes Status updates are rate limited. but 100 per day won't be an issue.
Current Twitter Limits
The current technical limits for accounts are:
From : http://support.twitter.com/forums/10711/entries/15364
The update limit is 1000 per day.But these are divided into intervals in which different amount of tweets are allowed per window. You can follow this thread.
Does this mean that status update API calls are also rate limited?
Yes,but not directly. As "The twitter API says that post messages are not rate limited" is true but not all POST requests are status update calls.
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.