Fortunately, there was a huge progress in the technology and thanks to bright engineers we now have access to the Internet. The most powerful source of knowledge which is publicly available. As the urban legends say there are hardly any things which you couldn't find in the internet, there things you will find beautiful, there are news and books which you can read online, but there are also things which we would never want to look at. That's the nature of the internet, everybody has access to it and is able to create his own content as well as browse and read stuff created by other people.
Internet would be a useless invention if we didn't have any tools for searching it. This why search engines like Bing or Google are now the most visited websites in the internet. Huge majority of people start browsing the Internet with typing some query into a search engine. People can look for some products to buy, reviews of the products they're going to buy, news and articles and many other things. And among those things there is one more which is not so popular to search using the internet - people. It can be very surprising to you, but it is possible to use internet as tool to find your old mates or just people that you want to learn more about.
Depending on the type of information that you have about the person you should use different tools to search for a person.
If you know a land line phone number of the person, it might be possible that you will be able to find details about him for free. There are actually a few websites which allow you to perform a reverse phone look ups free of charge and their databases are quite comprehensive. My first choice for such a search would be WitePages. Once you type a person's phone number, you will be given the person's name as well as the address. Of course there is a chance, that the guy has requested to remove his record from a phone directory and thus you will not be able to find it. If you decide to look for a person by his name, you should also think of a state where he now can live, since when you type simply his or her name you will surely end up with at least a few hundreds records which you will have to manually browse.
Spokeo is much more comprehensive than WhitePages and can provide you with information from social networks - which means that you can learn the person's interests and see pictures of him. Unfortunately, most of those information are not available for free, you will have to pay for access to them. The basic monthly fee for this is relatively low and equals $4.95. If decide to use the free version, you will still see the person's address, some limited household information as well as family members.
When type a person's name into Pipl search field, you will get a list of different results from the most popular social networks, such as MySpace, Bebo, Facebook, LinkedId, ClassMates, but you will also see which websites mentions this name. Spoeko will charge you for this, but Pipl will show you pictures associated with the given name for free. The pictures will come from pictures search engines as well as from social networks. Using Pipl website you can perform a free reverse cell phone lookup, but the amount of information which you can get will be small and usually it will be just the carrier's name.