What have they done that is scummy?

Not too long ago they advertised a deal that used Tim Ferriss' name to the material/product being advertised but then sent out an email next day or so that apologized for "mistakenly" associating Tim Ferriss with the deal when in fact he wasn't.

Earlier this year I unsubscribed from their newsletter. The unsubscribe page had a feedback survey stating that a reason was required. That really put me off. You can't require someone to give you feedback in order to unsubscribe from a newsletter (it may a violation of canspam, as well). I tweeted about it. They tweeted back an apology, saying it would be changed, but by that time the damage was done re my image of the company.

Try signing up for their spamletter. Then try reading halfway through their incredibly annoying spam when you get it. It reads like the transcription of a carnival barker.

I don't know if their practices are actually scummy. But their communication definitely has the same feel as most scummy MLM materials.

They're trying to mimic the supposed charm of the Groupon deals, but don't seem to have the skill to do so in a way that's widely appealing. YMMV as to whether Groupon has or ever had said skill themselves.