What's SMS.ac really all about? [updated]

I keep getting invitations from friends to sms.ac. The friends are the sort of people I'm certainly happy to communicate with, but I'm always suspicious of joining such on-line clubs because who knows what the real agenda is? I was certainly not surprised when meetup.com went C.R.E.A.M.y and started shaking down granny-tea-cosy get-togethers for dues.

Anyway, do any other savvy techies use it? Is it worth the (apparently free) registration? Do they seem like just the next generation of scum who happen to have taken some of my friends, or are they legit? I tried a few google searches but didn't find anything helpful.

Disclaimer: I have no problem with sites charging for services, and indeed, I'm happy to pay for several of my on-line services, but I can't stand bait-and-switch. B&Sers deserve keel-hauling, matey.

Updated Thanks to Mark Baker for pointing me to good reason to stay well away from SMS.ac.

[Uche Ogbuji]

via Copia