[lambda]

Heh, I was helping a colleague with some question, and I wasn't really sure about the answer, so we Googled and checked out the top hit on StackOverflow. Wound up being a question that I had answered a couple of years earlier, and forgotten the answer in the meantime.

[david-given]

I've actually done the next stage: researched a problem, found a really helpful Stackoverflow answer, which it turns out I had written, which was a reply to a question which it turned out I had also written.

The only disappointing thing being that due to causality constraints, I was unable to upvote past me's answer or further past me's question, which was a shame as they were both really useful.