Groupon's iPhone app has gone missing from the iTunes app store.

For three separate editors on different computers and different networks, a search for "Groupon" brings up one app from Groupon LLC, but it's the one for merchants, not the consumer-facing Groupon app.

While I was doing reporting for a big feature on the history of Groupon last fall, insiders all told me the future of the company was its app, because unlike the Groupon email it could house an almost unlimited inventory.

The apps' wide adoption was to be the company's first step toward becoming a "yield-management platform for small businesses."

So it's not a good sign for Groupon's business if it's gone for good!

We've emailed Groupon PR and Andrew Mason seeking comment and will update this post when we hear back.

Update: A Groupon spokesperson says the company pulled its app from the store as a precaution, after finding a bug. "Apple has expedited review of the new version and it should be available momentarily if it isn't already." As of 6:23 on the East Coast, it's still not there.

Here's a screengrab: