Sun's decision to move OpenOffice's licensing to the LGPLv3 sounds like a way to make sure that one of its bigger software products doesn't fall victim to software patent issues. After all, Sun went through a great deal of hassle to try and liberate Java from its legacy restrictions, so maybe it's just trying to make sure history doesn't repeat itself. A wise measure.
The LGPLv3 license allows the source code for OpenOffice to be reused in other products, even commercial ones (like IBM's revamp of Lotus, which I looked at a while back in a preliminary form), without similar licensing restrictions being imposed on the other products. However, the v3 license explicitly forbids any of the code released under its aegis from being protected by software patents.
Why do this? Well, for one, it's a pre-emptive way to avoid having people contribute code to OpenOffice and then turn around and claim ownership over either their contributions or the code as a whole. IBM, for one, as per the above example: if memory serves, it has been pretty friendly to open source -- certainly friendlier than Microsoft. Still, moving to LGPLv3 means any contributions IBM might make to the OO codebase through Lotus will be by definition unencumbered by patent trouble.
This issue might not mean much to the average user, at least not at first glance. But one of the ways this issue affects regular users is if a given software product that they've grown attached to is suddenly found to be infringing on a software patent. Whether or not the offending product is open source is a separate issue, although I'd wager an open source product is easier by far to liberate from accusations of patent infringement than a proprietary one.
Now for a little devil's-advocacy paranoia. I wonder, for instance, if someone might try to assert patent rights over a v3 contribution as a way of testing the validity of that license in court. Farfetched, maybe, but after the SCO debacle I'm learning not to assume anything is too farfetched. Another thing I do wonder about is whether or not this will inhibit third-party development and re-use of OpenOffice, at least until the real-world consequences of LGPLv3 are a little clearer.
That said, moving a product of OO's stature under the umbrella of LGPLv3 ought to provide exactly the kind of real-world shakedown testing that's needed here. And I doubt Sun would do something like this if it didn't have a fair idea of what was at stake.