Pledges at PledgeBank
The MySociety crew, who are responsible for excellent things like WriteToThem (which replaces FaxYourMP), have built PledgeBank. PledgeBank is a central clearing house for “pledges”—you say “I’ll write to the BBC and ask them to do things in ogg format as long as 30 other people will too“, and the site handles all the administration of collecting those thirty people. You still have to convince thirty people to do it, but at least you don’t have to try and track all their names and email them to remind them.

On a sort-of related note, I’m happy to report that the Canadian Broadcasting Corporation has an Ogg Vorbis trial going on.
http://www.cbc.ca/listen/ogg.html
They must have some cool hackers working for them, applying pressure from the inside.
16 hours later