Captive market PR company. They own some news-looking websites, and pay posters to post content. They're a small step above spam mills and several steps below real PR firms.
Much of what they promise, they can't deliver, and their "social media" stuff is normally treated as spam by legitimate websites and recognized as spam by the typical reader.
Do they post on DU? I doubt it. In fact, I doubt that there are any paid posters on DU. Paid posters post crap, because they aren't paid enough to produce quality content.
The one thing they really can't deliver is cleaning up negative comments about a brand or individual. Most of that stuff in on websites that wouldn't remove anything based on a communication from brand.com. I doubt they can do much in that regard.
Reputation management is a more or less legitimate industry. Most of it involved educating clients on what not to do online and how to mitigate issues that arise through effective customer care efforts.
But, if you see brand.com as a source of paid spam posts on DU, you're almost certainly incorrect. Since I started my first term on MIRT, I've watched spammers get detected and banned almost instantly. A very clever group of people on MIRT is very good at spotting spam as soon as it's posted and PPRing the spammers.