News Corp (NWS) social network MySpace allowed its users to sync up their status updates with Twitter only a week ago, but the move is already paying off.

The evidence? Just seven days into the integration, MySpace’s link shortener lnk.ms is the second most popular on Twitter, according to Twitter link aggregator TweetMeme. (Via TechCrunch.)

To be sure, just because MySpace users are filling Twitter with new links, that doesn’t necessarily mean people are clicking on those links — or providing MySpace any material traffic growth. And just because MySpace broadcasts to Twitter now, it doesn’t necessarily mean that MySpace users are logging into the site more frequently than they did before.

But it’s probably contributing some growth in both metrics — certainly a step in the right direction. (And something Facebook should implement as soon as possible.)

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