John Pozadzides of the Web analytics company Woopra wrote a guest post for ReadWriteWeb looking at the web’s top sources of referral traffic. He breaks it down in to the following categories: social network, social bookmark, search, and media.

Six versions of Google top the list for search before Bing makes an appearance. Facebook takes the cake in social networks, followed by Twitter and LinkedIn. In the social bookmark category, StumbleUpon leads, and in media, it’s YouTube.

Mashable’s Jolie O’Dell reports that a court in Komsomolsk-on-Amur, Russia has demanded a Russian ISP block access to YouTube because it hosted what it says is an extremist video. The Internet Archive and three online libraries were also reportedly blocked. As O’Dell points out, a number of other countries have also blocked access to YouTube at different times.

The New York Times reports that the House Financial Services Committee approved a bill that would effectively legalize online poker and other nonsports betting, overturning a 2006 federal ban.

Pocket-lint reports that Amazon claims ebook sales will overtake paperbacks next year. It’s a pretty astonishing notion, but not too hard to believe considering that Amazon recently announced that ebook sales have overtaken hardback sales.

Mobile Crunch has pointed out that RIM has purchased the domain BlackPad.com, speculating that a long-rumored BlackBerry tablet could be called the BlackPad.

News surfaced yesterday that a directory containing personal details of over 100 million Facebook users has surfaced on a file-sharing site. BBC News spoke to the man responsible who says he harvested the info for a security tool.

Back in early May, it was discovered that Google had invested in something called Recorded Future. Now Wired reports that the CIA is involved as well, in the company that monitors the web predicts the future.

Facebook launched the long-awaited Questions feature yesterday (in beta). Search Engine Land has a detailed walkthrough of the feature.

According to Ben Patterson at Yahoo News, citing information from Courant.com, U.S. libraries are loaning more DVDs on a daily basis than Netflix and Redbox are renting them. This make sense given that many libraries offer free DVD loans, and cheap prices on new releases.