But there is no way to really be sure. Because they may have filed something before or after (within the 1 year) public disclosure.
Its just a mutually assured destruction arms race. The system is broken.
Anyone would be free to use the patent. But trolls can't sue with it.
Then you whip out your defensive patents and demand that IBM licenses your IP for 3% of their revenue. (Win-win cross licensing ensues...)
Patent trolls are a different animal though. However, having some good patents may at least protect you from willful infringement (increased damages)
I wonder if it's time for a Patent Denuclearization... but I'm not exactly sure how that could look like.
Prior use in public would count as "prior art" and void a patent too.