YouTube Apps Suggest Videos to Watch Next Read about new options for YouTube apps, Twitter's latest startup acquisition, new Vine features and more social-media news.

This week's need-to-know social-media news.

Brands that use YouTube to promote their products or services will welcome the latest update to the video service's mobile apps: video overlays that suggest what users should watch next. Google calls it "InVideo Programming," which means that YouTube creators can cross-promote their channel's videos -- linking one video to the next so, ideally, a user will play all of them. While this feature is new on mobile, it has been available on the desktop version of YouTube since last fall, and is already used by more than one million channels, Google says.

The update also includes call-to-action overlays. You can share additional information about your videos with these overlays or use them as a space for brand promotion. As of now, the overlays are available only to advertisers who use AdWords for video, but Google plans to bring them to all channels before the end of the year. -- TheNextWeb

Twitter buys a startup: Spindle.
Twitter has purchased Spindle, an app that allows users to discover Twitter content created near to them. Spindle will shut down and its team of about 10 employees will move to Twitter's headquarters in San Francisco. "By joining forces with Twitter, we can do so much more to help you find interesting, timely, and useful information about what's happening around you," the company wrote in a blog post. -- SocialTimes

Facebook lets users comment with photos.
A new Facebook feature lets users comment on status updates with photos rather than just text. The feature came out of one of Facebook's employee hackathons. Photo comments are becoming available on the web to all users, but the feature is not yet available on the mobile apps, though photo comments are viewable in the apps. -- Mashable

Vine co-founders tease upcoming features.
Not to be outdone by Instagram's new video feature, the co-founders of the Twitter-owned Vine video app released have teased some upcoming features. It appears that full-screen videos and comments will be among the new features, though no one is saying for sure yet. "Over the next few weeks, we'll be introducing some exciting new parts of Vine," the company said in a blog post. "As always, we'll share details on updates as we release them." -- AllThingsD

Use social media a lot? You might be a narcissist.
A new study found that frequent tweets and Facebook status updates were highly correlated with narcissistic traits in both college students and adults. "Facebook is a mirror and Twitter is a megaphone," researchers from the University of Michigan wrote. People use social media "to boost their egos and control others' perceptions of them," they said. Narcissistic young people favored Twitter, while their older counterparts tended to rely on Facebook to garner approval. At this point, it's unclear whether Twitter and other social-media platforms lead to narcissism, or whether they simply provide an outlet for existing narcissism in some users. But you're free to ponder this question next time you see someone tweeting multiple times an hour. -- AllTwitter