...I am working with a parents' group which insists on using Yahoo! Groups to manage an email list rather than use Google Groups.
Now I am one who vigorously shuns dogma when it comes to technology, so I'm willing to reconsider my preference for Google in this domain -- especially given vehement instruction by one of the stakeholders in this particular group.
I asked myself, why do I prefer Google Groups over the more mature and much more traditionally used Yahoo! Groups? I think it has to do with how the advertising is delivered.
When I use Google Groups (or gmail), the advertising is something to which I (the actual beneficiary of the service) am exposed. When I use Yahoo! Groups (or Yahoo! email) the advertising is sent to my friend. Or to say it another way. The way that I pay for the "free" service I receive is that I give my friends over to Yahoo! so that they can advertise to them.
This screen shot tells the tale. The area under my comment bubble, and the area encircled in red are both advertising patches sent to the recipient of my message.
Yahoo! Listen up! When we said "permission marketing" we meant that you'd GET our permission. Not simply assign it to yourself on our behalf.