IP Addresses and Cookies:-

Every machine connected to the Internet has a unique Internet Protocol (IP) address, including your computer. You may have a static IP address or it may change each time you go online. Either way, you are tagged with a unique identifier every time you surf the Web.
An IP address is necessary for the Internet to work. It is literally the address of your personal computer on a vast computer network -- like a single house on a crowded street. The only way aWeb server can send the contents of a Web page to your browser is if it has your computer's address on the network.
IP addresses, in and of themselves, do not contain any personally identifiable information about you. However, if you're signed up with an Internet Service Provider (ISP) -- which is the way most of us get our Internet service -- then your ISP can easily link your IP address with your name, home address, phone number, e-mail address and even credit card information.
Don't get paranoid just yet: In general, ISPs have fairly strict privacy policies. They won't give out your personal information to any random person who asks for it. However, under laws like the U.S. Patriot Act and through subpoenas from the police and federal agencies, an ISP may have no choice but to supply personal information related to an IP address.
Cookies are another way for an outside source to track your Web surfing habits. Cookies are tiny text files that are saved in your Web browser when you visit a Web site. The file might contain your login information, your user preferences, the contents of your online shopping cart and other identifiers. These cookies make your Web browsing experience more personalized and customizable. They're designed to save you time when you visit your favorite sites. They're also designed to help advertisers tailor their messages to your personal preferences.


Piecing Together Your Online Identity:-

Cookies and IP addresses alone may not give away your personal information, but when these clues are combined with other Web surfing data -- like your search history -- you could unwittingly disclose your identity to hackers, scam artists or government investigators.
Search engines routinely store search queries associated with your IP address. Google stores search queries for nine months and MSN stores them for 18 months [source: Privacy Rights Clearinghouse]. By examining hundreds or thousands of search queries from the same IP address, it's possible to deduce someone's identity, particularly if they have done map searches on their home address or entered their Social Security number.
Another threat to online privacy involves Web e-mail accounts. If you use the same Web site for both your e-mail service and Internet searches, you might be leaving a very clear trail for hackers and cybercriminals to follow when you go online.
For example, if you use Google as your e-mail provider, then you need to log in to Gmail.com for each e-mail session. Any Google Web searches you conduct while logged in to your e-mail account will be associated with the same IP address as your e-mail account. From there, it would be easy for a hacker or other third party to associate your searches with your e-mail address -- and to use this information to send you customized spam or other e-mail scams.


Anonymous Proxy Servers:-

Every time you type a URL into your Web browser and click Enter, your computer sends a request to aWeb server, which then delivers the Web page back to you. To do this, the Web server needs to know yourIP address. So much for surfing anonymously, right?
Not necessarily: One way to avoid revealing your IP address to every Web server you contact is to use a proxy server. A proxy server is a machine that sits between you and the rest of the Internet. Every page request you make goes through the proxy server first.
An anonymous proxy server is a special kind of proxy loaded with software that erases your IP address from any page requests and substitutes its own. When the page is sent back by the Web server, the proxy server then forwards it along to you free of any additional software scripts that might compromise your identity.


Privacy Settings in Your Browser:-

Anonymous proxy servers are a great way to mask your IP addressonline, but there is still plenty of information about your Web surfing habits stored on your computer. Luckily, it's easy to control your privacy settings directly in your Web browser.
One of the simplest ways to cover your online tracks is to manually delete your browser history. All Web browsers -- like Internet ExplorerFirefox, Safari or Google Chrome -- allow you to delete your Web surfing history.
Follow these instructions to delete your browser history:
  • In Safari, go to the History menu, scroll all the way down to the bottom and click "Clear History."
  • In Firefox, open the Preferences box from the Firefox menu. Choose the Privacy tab. Go down to the section on Private Data and click "Clear Now."
  • In Google Chrome, go to the Tools menu, select "History," select a recent Web site and click "Delete history for this day."
  • In Internet Explorer 7 and 8, this process is a little more complicated. Go to support.microsoft.com and follow the directions there for assistance.
Note, however, that any network administrator -- at the office or even at your ISP -- can access your surfing history on the network level, even if you erase it on your computer.


Anonymous Registration:-

Many free and subscription Web sites require you to register before using their services. This usually requires three basic things: an active e-mail address, a username and a password.
Aside from the security risks of giving your e-mail address and other personally identifiable information to a random Web site, a lot of people simply don't want every Web site they visit to know who they are, and certainly not how to contact them.
For security purposes, experts recommend that you don't use the same username and password to access all of your Web sites and services. The danger, of course, is that one of these sites will -- either maliciously or accidentally -- hand your information over to identity thieves who will use your universal username and password to access your online bank account or other highly sensitive Web services.
Another annoyance is that many Web sites have no problem with selling your information to third parties who will then load your inbox with spam. Some sites allow you to opt out of receiving e-mails from partners, but it isn't always clear which boxes to check or uncheck.