Flixster is spamming me - how not to do opt-in marketing

This morning when I looked at my gmail, I found about 30 emails from Flixster, a site that I once signed up to in order to test their Facebook Connect implementation. When I signed up, they asked me to import my Gmail contacts, which is fairly common practice right now. Once that was done, the spamming started: they preselected all of my gmail contacts for an "invitation" - consequently, I invited no one. Now it gets worse: although I never authorized this, Flixster remembered my contacts for me (not good practice!) and now sent me these lovely emails suggesting I "might know" these people - of course I do - they're in my gmail address book....
I'm a big fan of the viral loop, the famed viral coefficient and the power of referrals - but please play by the rules, don't abuse the trust that people extend to you and most importantly - don't spam people!