Retailmenot breaks the affiliate T+Cs of major partners like Amazon and eBay by clickjacking a new window open to the site (and cookie set) as the user peruses discount codes on RmN. I'd say that's a potential area of future risk, even if the sites don't care.
Can I call bullshit on their claim of "full incoming item traffic (750 items/s)?
I assume this is user generated content, not automated uploads from e-retailers? Regardless of where it comes from that would equal 2.7 million items uploaded per hour, 62 million per day. FFS Google has only indexed 2.2 million items from their site.