United States diplomacy may now have an interest in Edward Snowden staying where the world can keep an occasional eye on him. Not that we want him in the spotlight, but if he were to disappear, almost everyone would assume we were responsible. He wouldn't be the first person "renditioned" to a CIA black site prison that we tried to pretend didn't exist.
This means any government or organization that wants to stir the pot could kidnap him and dodge the blame. They'd just need to spirit him away without being detected.
Mr. Snowden himself might want to try that tactic, if he's willing to drop off the face of the earth for a decade or so. There may be several countries that would be happy to help him do just that. In fact, maybe he's done it already. We haven't heard from him in a few days. We could hardly expect him to leave a message, "Bye now, I'm going into hiding." Presumably the Guardian and The Washington Post now have all the juicy tidbits he could give them, though they may trickle out the stories bit by bit. So what does Edward Snowden need to stick around for? He could just kick back and watch from anywhere on earth that has an internet connection. After all, any time he sticks his head up the debate tends to shift from whether our government should spy on us back to whether he's a hero or traitor. He even said he doesn't want to be the subject of the debate; he wants us to look at what the NSA is doing.
For Snowden to disappear might be our intelligence agencies' worst nightmare. My guess is that they're still trying to piece together what information he has, or might have. There are probably plenty of things they could quit worrying about if they could "interrogate" him. If he's holed up in an airport in Moscow, our spooks at least have some chance of keeping track of who he's talking to. If he were to disappear, they'd have to assume the worst.
If our intelligence folks had been sly enough to pretend from the beginning that Snowden was a low-level computer geek who didn't really have access to anything important, we likely could have let him go and then made arrangements with his host country to quietly keep tabs on him. But we can't sell that story now.
I don't think it's very likely that Edward Snowden will just disappear. But I could believe the CIA and NSA are already asking the Russians to please keep a close eye on him and make sure he doesn't.