You've run into a Twitter follow limit on your account. Even if you do find an automated way to figure out who is not following you back and want to unfollow them, don't do it. It will get your Twitter account suspended. It is against the Twitter rules.
Drip feed is a paid Professional feature. Only you can decide whether the free features are worth it.
Links are tracked by SocialOomph account, not by Twitter account.
On the upload page, click the little bubble with the question mark that's located on the far right edge of the browser window. It will give you all the details.
Tweets in the reservoir are single-use entities. Hence, they cannot contain spinnable text. Since reservoirs can feed both Twitter and Facebook simultaneously, the smallest number of characters, 140, is the limit applied to the allowed update length.
Drip-feeding does not support spinnable text. Each update in the reservoir is a single-use entity, which is removed from the reservoir once it has been published.
Login, and look for the button that says, "Click Here To Test Drive SocialOomph Professional". Then activate your free trial.
Please double check that the date on the post is not still set to 2011.
This is a good starting point: http://en.wikipedia.org/wiki/Rss
It must conform to the RSS specification.