One of the biggest years in the search engine world was 2005. That January, Google united with Yahoo and MSN for the Nofollow Attribute, which was created in part to decrease the amount of spammy links and comments on websites, especially blogs. Then, in June 2005, Google debuted personalized search, which used someone’s search and browsing history to make results more relevant. That November, Google Analytics launched, which is still used today to measure traffic and campaign ROI.
The nofollow attribute was launchedto stop comment spam links in blogs. Nofollow is a value that can be assigned to the rel attribute of an HTML a element to instruct some search engines that the hyperlink should not influence the ranking of the link's target in the search engine's index. It is intended to reduce the effectiveness of certain types of spammy internet advertising because their search algorithm depends heavily on the number of links to a website when determining which websites should be listed in what order in their search results for any given term. Why would you want to use the attribute? Blog publishers, forum operators, sites with guest books and others who allow anyone to contribute in some way to their web sites have suffered when people have used these systems to spam them with links. The tag can be used by anyone anywhere, of course. It's not just for use with blog comment areas or forum posts. For example, people might use it if they publish dynamically generated referrer stats and visitor information.