Google Groups vs. Yahoo Groups

I’m a member of several Yahoo and Google groups scattered across multiple Yahoo and Google accounts. They’re both great services as I depend on mailing lists and the like quite a bit to stay up to date on whatever particular technologies I happen to be using at any given time. One difference between the two, however, is the amount of clutter they stick in the emails. I thought this was an interesting comparison of each services message footers (reduced to roughly 40% actual size):

listfooters.gif

My favorite part of the Yahoo footer (which is from a SharePoint Yahoo Group) is this at the very bottom:

Chat over IM with group members.
Dog Groups on Yahoo! Groups
Share pictures & stories about dogs.

Not sure what kind of keyword system Yahoo is using there to drop ads in…