At my previous company, we had a patent lawyer who would always ask around if anything we developers did were patentable. I would always downplay what I was doing and come up with things that might be prior-art.

My thinking is this: Even though the company would only use it for "defensive purposes" (which I believe), you never know who owns the company tomorrow. And you are not going to work there tomorrow either, so you might be the one being sued.

Instead, I would try to get permission to blog about it, so it is available for everyone -- including my future self.

I recommend everyone else do the same!

(Throw-away account - I'm not sure future employers want this)