Some websites display strange shaking windows...what is that for?

Question

The windows normally tells you these :
-You are the 999,999,999,999th visitors, you have won!
-Get these cute wallpapers, just click here.
-Live and work in the USA with green identity card!
-You have 1 new message, please click here to read it.
-This is not a joke, you won! please click here to obtain your prize.
-This is strange! they know what will happen to you tomorrow! just click here to ask.

I heard these windows were use to trap people who misbelieve it and hack their computer with harmful viruses. If this is true, why is these window not blocked? and why several websites allows that to display on their webpage?

Answer 1

Most websites include some form of advertisement to cover their operating cost and generate profit. In many cases, the advertising is done through an external advertising company and handled through "includes" in the website pages (headers, footers, context links (i.e. Intellitxt), etc...). The website you visit can generally specify that they want to limit to particular advertisers categories (i.e. a site focused on younger users might have a lot of cell phone, music, or clothing ads but would prohibit adult content ads) but might not specify exactly how they advertise (images, text, audio, rich content, etc...). Advertisers are merely trying to compete for business and employ creative techniques to get people to their site. Most people will ignore the ads but enough people are interested so the business model exist. The shaking ads, animated ads, interactive content (punch the monkey for example), etc... are all attempts to attract new business.

As for the "trap", it really depends on the sites you are visiting. Reputable sites will tend to restrict harmful external links while less reputable sites tend to have a lot of the more dangerous content. If you keep your anti-virus software up to date, your operating system patched, and use a bit of common sense you can often avoid having your system compromised.