Today's Webmaster Help video from Google doesn't appear to be an April Fools' joke. It's just Matt Cutts responding to a question like normal. The question at hand is probably something a lot of people have wondered:
I've seen multiple websites that appear in the #1 spot for various keywords, whose backlink profiles are pretty low quality (i.e. lower quality blog pages). Why wouldn't Penguin have moved these sites further down in rankings?
"There's a lot of possible reasons," says Cutts. "One is, Penguin is geared for certain types of spam, but it's not geared for every type of spam. For example, it doesn't help with hacked sites. So if a site is being propelled up the rankings on the basis of illegal hacking of sites, that's not something that Penguin attempts to tackle. There are other other algorithms that try to tackle that."
"The simplest explanation might just be that we don't want that to rank, but the algorithms haven't gotten good enough yet. We need to make sure that things get better. If that's the case, we're happy to get spam reports or if you want to show up on a forum, or a webmaster forum, and say, 'Hey, here's a site that doesn't look like it should be ranking,' we're happy to hear feedback like that."
He also notes that unless you're the site owner, you may not be getting the complete list of links for that site.
It seems fairly likely that much of the time it's that explanation about the algorithms not being good enough. As Google has noted on plenty of occasions in the past, no algorithm is perfect, and Google tweaks them all the time.