Yeah I edited my response while you were typing yours...
As to when I heard about the thumbnail. the first week I was here when animated GIFs were still working in the thumbnail (seems to have changed) there was a pretty explicit animated GIF blow job floating around out there. It was actually the first time I ever saw a post with negative votes. I didn't know the flag existed, so I was like "how is that negative?" and that's when they told me where it was and why it was flagged.