You don't have to subscribe, and you can sign up for twitter without getting updates no your phone.
I actually have updates turned off on my phone completely, just use the desktop client, or a phone client when I'm interested.
Twitter is really like a hallway conversation. If you're there, you might hear something interesting, if you're not, usually not a big deal.
The site has an account at http://www.twitter.com/sqlservercentrl