If bit.ly would put in the referer logs the url where the bit.ly link is, then bit.ly would be much better for recipients of traffic from bit.ly.

As it is, the actual producer of the content being linked to has no idea where that link is on the web. Is it in a tweet? A blog comment? Where?

Bit.ly and other url shorteners are robbing content producers of valuable traffic information and giving it to the linker, but I would argue that it is much more important for the producer of the content to know who is clicking links and from where than it is for the person who links to the content.

This, of course, is one problem in addition to the increased layer of indirection and reduced reliability of content acquisition in the future due to the disappearance of the shortener.