This is used quite extensively across the web, but I'm wondering whether it is actually necessary.
Alot of animated banners/carousels on websites use navigation or paging links so that you can jump to a particular banner within the set. The problem is that alot of these paging links don't give any indication of what banner you will be scrolling to if you clicked it. So should they be used, and if so, is it necessary to offer a tooltip on hover?
This also brings up a point about the number of banners to include in a set. If paging is required then are there too many banners to scroll through? Is a previous and next link enough to offer the user?
Screenshot below of an example of paging within a scrolling web banner (paging is in the top right):

I personally stand by the approach of not including a carousel at all, because users are trained to miss moving objects (the mind portrays them as adverts and gives them little importance). But if a carousel is to be used, I'd only have a next and previous options available. Auto scroll is fine, but the user should be able to halt at least on hover.
– Daniel Meade Oct 09 '12 at 11:41