Identifying users who are spamming the Zeitgeist

December 22, 2009

As SlideShare has grown, it has attracted more people. Not surprisingly, it has also attracted some spammers. On looking closer into it, we realize that there are different types of spam.

One is the drive-by spammer who uploads some spammy content and leaves. Its relatively easy to identify this and take the content down.

Harder to detect and remove is "social spam". For example, a user following thousands of users in the hope of getting a few users to follow back, and therefore getting more distribution of their content. Or users who favorite a lot of content hoping to get people to visit their pages. Or who comments on a lot of presentations with the same hope.

We have started identifying circles of such users who engage in "social spam". While this is very common on larger sites like Twitter, we want to kill it in to root while its early days on SlideShare.

The community Zeitgeist has attracted its own share of social spam. We have algorithmically detected patterns where a few users are nominating specific users hundreds of times. Closer analysis shows its probably the same person getting nominated / doing the nomination. We have put algorithms into place that will remove all such nominations from the system. If we find evidence that these same people continue trying to spam the Zeitgeist (either by making the nominations, or if you are the person who is getting nominated in this way), then we will ban the account.

Its perfectly ok to ask friends to vote, its not ok to login as another user (or ask another person) to vote hundreds of times. Our algorithms will detect voting fraud - anyone either casting votes like this, or getting such votes will be banned from the Zeitgeist. The goal of the Zeitgeist is to discover people whose content is genuinely popular among a large group of users. We will be doing everything we can to make sure to find genuinely popular users, not those who are manipulating votes.

Update: Our engineers have continued uncovering spam vote trends and removing those votes from the system. These will soon be reflected on the Zeitgeist page itself.