It's a modern kind of shit talking employed by large corporations in conjunction with astro turfing (pretending to be an unbiased commentator, when you're really as biased as can be) to dissuade people from going to a competitor.
Because saying stuff like "I dunno dude, there's been reports of a lot of problems with Product X" is a lot more persuasive than "Product X sux!!!", especially when you don't know the poster was paid by Company Y, a competitor, to say it.