2005: Google, in partnership with Yahoo and MSN, launches the nofollow tag to combat comment spam (we’ll learn more about this in the next section).
2009: Google has removed the PageRank distribution feature from its Webmaster Tools.
2013: In November, the last known update to Visible PageRank occurred.
2016: Google officially shuts down the Toolbar for public use.
Google's war on spam links
Google's ranking algorithm at the time was very simple - high spain mobile database PageRank and keyword density were the only two things that mattered for a page to rank high on the SERP. As a result, web pages became stuffed with keywords and website owners began to manipulate PageRank by artificially increasing spammy backlinks. This was easy to do - link farms and link selling were there to provide a "helping hand" to website owners.
Google decided to fight back against spammy links. In 2003, Google penalized the website of the ad network company SearchKing for manipulating links. SearchKing sued Google, but Google won. This was Google's way of trying to limit link manipulation by everyone, but it didn't lead to anything. Companies like SearchKing went underground, and their number multiplied.
In the early 2000s, blogging was gaining prominence, and many SEOs knew that Google viewed links as votes.