What are the Generator and Formatter tags?

The Generator and Formatter tags specify the system that has generated the metatags, in this case PrePromote.

Their purpose is to allow tracking and analysis of the use of different systems across the web. They have no promotional significance unless people manually view the source code.

They have no affect on your pages' rankings so you can remove them without any adverse affects. It would be helpful for the Internet community as a whole, however, if you could leave them in.