This is what i have promised to write in last post. iframe...not a dangerous thing but some sites use it in bad manners. First of all, i will give you some idea about iframe.
What is iframe?
An iframe is a way for a webpage to load content from another webpage or website. Iframes aren't bad in themselves, but they can be used for bad purposes.
The main problems with this are when the iframe is used for cheating, or if they carry malicious content like viruses.
Cheating with iframes in this case is happening by someone creating a webpage, putting banners from third party advertisers on the page, and then putting the entire page into an iframe way too small to see all the banners. In this way, the advertisers at the 3rd party network have to pay each time their banner loads, but no one can see the banner because it's hidden in the iframe.
Note*
If you think of a regular sized banner that we see on the net, they are sized at 468 pixels by 60 pixels. Now imagine putting this entire forum webpage into that banner size, you wouldn't see very much of the page, you'd just see a little bit of the logo at the top left of this page...
So imagine that the rest of this page was covered in third party advertising banners instead of posts, and it was stuck in an iframe that size, you wouldn't be able to see any of those banners, but if you came across a page loading that iframe, all those banners would load without you seeing them and the advertisers would have to pay for that loading because they think when the banners load, someone is actually looking at the whole webpage.
Some sites put 19 webpages with third party banners into an iframe that size and you couldn't see *any* of those banners at all. That's a lot of cheating and a lot of stress on your browser as it tries to load that mess.
More often iframe cheating is referring to using 0 iframes. That means instead of a 468x60 regular-sized banner imagine a full stop/period on a page. That full stop/period is 1 pixel by 1 pixel. So 0 pixels by 0 pixels can't be seen at all. Some iframe cheats try to put webpages into iframes that size! They can also put autosearches into iframes, where a robot program will click on search results from PPC engines automatically instead of you searching for something you're interested in and then visiting one of the results.
Another thing that can happen is that the iframe can contain virus codes. A page with a virus on it inside a 0 iframe would look totally normal, because the 0 iframe is invisible, but when you visit the page, your computer could be infected.
SO BE CAREFUL