The amount of gaming-related YouTube content has exploded in recent years. There are loads of official trailers and promotional videos, plus reviews and other footage from independent sources. Then there's all the content that's presented as independent coverage but financed or influenced by game publishers and developers. Eurogamer has published an excellent article exploring some of the more unseemly practices being used to put favorable impressions in front of millions of eager eyeballs.
The sordid details aren't terribly surprising. Some YouTube hosts are reportedly being offered cash to cover specific games, and the terms can require that bugs and negative elements are left out of the discussion. There are product placement deals, as well, and possibly payola in exchange for "liking" certain videos. Yogscast, a popular channel in the UK, even exchanges coverage for a cut of game revenues.
Other media aren't immune to these practices, of course. The rest of the web is littered with so-called advertorial content and other corrupted opinions. But bloggers and journalists are obligated to disclose sponsored content (even though some of them don't). That requirement should also extend to YouTube, where there seems to be less acknowledgement of outside sponsorships.
According to popular host John "TotalBiscuit" Bain, YouTube is more prone to influence than traditional media. It's certainly less formal, and the hosts are typically younger, with no background in journalism or related fields. However, Bain says "the majority of these channels don't label themselves as journalists or critics," adding that "there is no pretence of authority or independence." He likens the talking heads and faceless voices in gaming videos to talk show hosts. Those folks shill for companies all the time.
The EuroGamer piece underscores a larger problem with online media in general. Corporate influence appears to be growing, and it's not always disclosed. Separating the signal from the noise is becoming increasingly difficult.