Digg, a website that ranks and displays news, blogs and other items based on recommendations from its visitors, has responded to efforts to manipulate the rankings by dropping its list of most active users.

In an open letter, Digg founder Kevin Rose said the top users who were spending "hundreds if not thousands of hours" identifying the best stories for others to read wound up getting blamed for much of the efforts at manipulation, which includes offering cash and other incentives to vote favourably for certain items.

The list of top users, which Rose said had been created to recognize those who worked hard to make Digg useful, also potentially gave companies wishing to publicize their stories an easy way to find people whom they might be able to influence.

"After considerable internal debate and discussion with many of those who make up the Top Digger list, we've decided to remove the list" effective last Friday, Rose said.

Rose acknowledged that manipulation does occur, but believed it's ultimately not successful.

"We're not surprised that with the gaining popularity of Digg there would be some that would try to manipulate the system for a variety of reasons," Rose said. "The number of users engaging in this behaviour has been minuscule in relation to the overall size of the Digg community."

David Sifry, founder of the blog search site Technorati, said the attempts to game Digg underscored its growing popularity.

"This is what happens when you are actually successful in the social media space," Sifry said. "Any ecosystem of value will have parasites. The real question is how do you deal with it. The Digg guys have done a really good job at understanding the gaming behaviour."