When this astonishing video was posted on YouTube a month ago, Web users immediately took it upon themselves to solve what was either a mind-boggling mystery, or a very clever hoax.

The YouTuber who posted the candid camera footage describes the person caught on tape as "an uninvited guest living in my apartment". He goes on to explain that he took the footage to the police, resulting in the arrest of the woman, who they confirmed was living in the loft of the building and climbing into the YouTuber's apartment every night to eat, go to the toilet (or rather, the sink), and watch television.

The video is a fake; a marketing campaign for an accommodation rental website (www.nakedapartments.com). It's very well done however - the only possible giveaway is at the end of the video, where you get the feeling the actor knows he's being filmed. Web users certainly had a hard time deliberating over its authenticity, causing just the buzz the company desired.

Fake amateur videos are increasingly popular when it comes to promoting a label or a film release. It's been done in Russia, the US, and even by press freedom activists Reporters Without Borders.

What do you think of this kind of marketing? Do these videos discredit information published on the Internet? Or are they beneficial for keeping Web users on the ball?