Google registered domain names yesterday for an “Open Patent Pledge”.

When Google acquired Motorola Mobility for $12.5 billion, it was clear that a big reason for its purchase was Motorola’s patent portfolio.

Now it looks like the company might be getting ready to make some sort of “Open Patent Pledge”, although what that actually is remains to be seen.

Yesterday the company registered OpenPatentPledge.com (and .net/.org) as well as OpnPledge.com. (It couldn’t register OpenPledge.com, which is owned by a company in South Korea.)

Perhaps this is related to Paul Graham’s idea of a Patent Pledge of “No first use of software patents against companies with less than 25 people.” Or maybe it’s like IBM’s open source patent pledge. Another idea is it’s related to its FRAND proposal for licensing Motorola patents.

We’re likely to find out soon.