The trend of hosting multiple sites on one server has gone, and right now it is in fashion to host one site on several servers. Well, sites that have traffic or a lot of content ofcourse. Take for example an image gallery that has got a lot of images, which is updated automatically from several websites onthe web. Did you knwo that hosting images or content on your site giving proper credits to the copyright owners of the images or by linking to them is never illegal?

So, if you get an idea to start a site like that, you can never do with just 1 server. You will become someone like flikr, attract images from everywhere, and put them on automated image galleries, and this way traffic will automatically come over to your website, and with that traffic you could make a lot of money selling ads and stuff.

This is why today you might see people ordering 10s and 100s of servers all at one go with the datacenters at good discounted rates, and network them internally to make them into a grid, or make them into one single server with loads of processor resources memory and disk drive space. Some people say that if you make a grid out of 2 P4 processor computers, you will get the power of 2^n = 2^2 = 4 computers. That way if you make a grid out of 128 computers, then the power that you would be able to derive would be of 340282366920938463463374607431768211456 computers. Maybe thats how Wikipedia is so powerful and fast though it is the 2nd website after google that receives the most number of visitors. But is this calculation correct? Thats a very large number, and if someone wants computing power why dont they just rely on this and why do people go for mainframes and stuff?