Every once in a while, I poke around in my spam filter in my gmail accounts. I virtually never find anything, but today I did. 3 emails from gopsenator.com in one account. Three from nrccmail.org, and some other gopsenator.com in the other. All fund-raising emails. If potential donors (sorry senators, I'm not a donor) don't get the emails, then funds are decreased.
So, built in bias? Lots of clever dems subscribing then marking as spam? Who knows. I'll do my part by un-marking them as spam and deleting them manually.