Facebook is testing a built-in-house application that will allow users to send impermanent photo messages to one another. Many are comparing the app to Snapchat. It will launch before the end of 2012, sources say. More here.

Apple stock fell below $500 for the first time since February this morning following a downgrade to neutral by Citigroup. It dipped to $499 at 6:55 a.m. Eastern this morning, reports Bloomberg. Why? Venturebeat reports: “In a note last night, Citigroup analyst Glen Yeung pointed to reduced supply-chain orders that ‘bring into question the strength of the iPhone 5.’ He proceeded to cut his price target on Apple’s stock to $575 from $675.” More here. 

Yesterday Germany’s Data Protection Commissioner issued a ruling that Facebook’s real-name policy violates a German law. Facebook users must be allowed to use pseudonyms to maintain online freedoms, as protected by law. More here.

In a deal announced on Monday, Nielsen and Twitter are partnering to become the official arbiters and measurers of television ratings based on Twitter activity. Standard Neilsen ratings are best for big television events like the presidential debates or a big sporting match, which people tend to watch on an actual television. But Twitter captures the “second-screen” experience of television shows watched on computer screens after they’ve been aired on TV. More here.