It’s not a sure thing just yet, but seems to be pretty close. I’m told that Discovery Communications would pay around $30M for the San Francisco-based, ad-supported online video network. It distributes and markets short programming devoted to special interests including gaming, tech, and entertainment. Execs believe that Revision3 would enhance Discovery’s online presence — and possibly its programming. Some of Discovery’s TV shows could be edited to work on the site, and some of the Web productions on Revision3, which are shot in HD, might be adapted or expanded into more conventional programs for cable channels such as Discovery, Animal Planet, and TLC.  Founded in 2005, Revision3 generates about 100M views per month according to web site TechCrunch which disclosed the negotiations. About 72% of its viewers are between 18 and 34. If the deal goes through, the plan is to keep Revision3’s management in place under CEO Jim Louderback. This would be Discovery’s biggest Web acquisition since 2007 when it paid about $250M for HowStuffWorks.com. Revision3 investors include Mark Cuban, Marc Andreeson, Floodgate, and Greylock Partners