Tumblr has succeeded in wooing TV to its platform, or at least Viacom. The plan it seems is to co-brand campaigns that tie to specific shows on their channels like MTV and Comedy Central. If it works and begins to grow in reach it might be a whole new way for TV to use social media.
YouTube appear to be rolling out a version of their video masthead ad format to mobile devices. However, instead of the usual banner design, viewers to the "What to Watch" section of the app, will see an ad that looks like an a regular video tagged with an 'Ad' identifier.
Google is updating the search algorithm again. One possible effect to video is the targeting of sites that use advertorials without full disclosure. There are a number of other black hat spamming techniques being addressed, but Google's Matt Cutts explains it better than I do in a video Google released.