1. How many of you know about the hosts file function in windows?It's a text file without a file extension that is intended to map IP addresses before accessing a domain name server to speed up the access. Now with the growing cyber concerns in the recent years,this mapping function is being additionally used to take a more preventative role in ad blocking and stopping spyware.This is located inside the >system32>drivers>etc folder.
2. To explain it more simply When a address like http://www.bbc.co.uk/ is placed into your browser, the Hosts file is consulted to see if you have the IP address for this site. If you do, then you get directed to the site IP,but since most of the times it is not there,computer asks for the IP address from your ISP to find sites.
3. It is here,that this function has recently been started to block ads, banners, 3rd party Cookies, 3rd party page counters, web bugs, and even most hijackers. In many cases using a well designed HOSTS file can speed the loading of web pages by not having to wait for these ads, annoying banners, hit counters, etc. to load. This also helps to protect your Privacy and Security by blocking sites that may track your viewing habits, also known as "click-thru tracking" or Data Miners. Simply using a HOSTS file is not a cure-all against all the dangers on the Internet, but it does provide another very effective "Layer of Protection".
4. http://winhelp2002.mvps.org/ is one site that I found worth as the purpose of this site is to provide the user with a high quality HOSTS file.This includes a ready to download hosts file that can replace your existing hosts file likely to be empty.The hosts file is kept updated on a regular basis.As on date the last update was available for 28th Feb 2012.So this site has a list of known ad and malware site IP addresses that are redirected at 127.0.0.1.The site advertises saying " THERE IS NO PLACE LIKE 127.0.0.1.