I'm using software which apparently doesn't use the API. I'm running 12 accounts and sometimes I'll get the error message: Rate limit exceeded. Clients may not make more than 150 requests per hour. Following and Unfollowing can't count, or else I'd be hitting the limit within minutes. Updating the following/followers list DOES count as a request. But I'm unsure on the other functions you can do on Twitter that count towards the max 150 requests per hour. Does anybody have a good idea about what counts as a request?