Their minions write a lot of blub comments so that the comment count is higher than the voting count of a story which equals to flagging a news!!
Another very visible behaviour is that they very quickly push positive news out as soon as there is a negative news.
If you track HN stories about Microsoft with a third party HN tracking service, you clearly see evidence that unfavourable HN stories about MS vanish very quickly by flagging or overflowing the story with a lot of blurb comments to hide them. And on the same day another often minor but positive news surface and sits on HN frontpage for several hours - and of course flagging all comments that even try to hint the privacy issues with Win10 or anything remotely normal comment that isn't overly hyping their software/service.