Google’s Matt Cutts is back online, and cranking out the Webmaster Help videos. He tweeted a link to the second of the latest series today, and this one is about referer spam coming from a YouTube video.

The user-submitted question is:

Why does a certain YouTube video appear to be visiting my blogspot blog? Take this video for example, it keeps appearing in my Blogger Dashboard as a referral..

Cutts says they looked at the video, and found in the comments that there were multiple people complaining about the same problem – that the video spammed their blog.

“This is an instance of what we call referer spam,” he says. “A referer is just a simple HTTP header that is passed along when a browser goes from one page to another page, and it normally is used to indicate where the user’s coming from. Now, people can use that, and change the referer to be anything that they want. They can make it empty, or there are some people who will set the referer to a page they want to promote, and then they will just visit tons of pages around the web. All the people that look at the referers see that, and say, ‘Oh, maybe I should go and check that out.’ And the link – whenever there’s a referer – it doesn’t mean that there was necessarily a link, because you can make that referer anything you want, so there are some people who try to drive traffic by visiting a ton of websites, even with an automated script, and setting the referer to be the URL that they want to promote.”

He notes that some of the other comments on the YouTube video say that its creator is well known, and has no reason to spam people. Cutts notes that it doesn’t necessarily have to be coming from the actual creator.

“The thing to know is that there’s no authentication with referer. Anybody can make a browser, and set the referer,” he says. “You can’t automatically assume it was the owner of that URL if you see something showing up in your dashboard.”

Basically, you should just ignore it, he says.