This is more a curiosity than a pressing question (even though I tagged it as "bug"). But I noticed that my account "tags" seem to change over time. I figured some algorithm looked at my questions and answers and somehow decided to tag what it thought my specialties to be, accordingly. Then, today, I noticed my tags as "greek", "fonts" and "siunitx".
Now I can understand "greek" as a tag, since an old answer of mine recently received some attention concerning upright greek symbols. Fonts? OK, I'll buy that one too, though it is a bit of a stretch. But "siunitx"???! I am embarassed to admit it, but I've never even voluntarily loaded the package (except if the OP's preamble does). Five hours ago, I left a comment on Getting ! instead of comparison sign < in cases that mentioned the word "siunitx". The comment got 3 upvotes.
Is that apparently enough to tag me as... what? Proficient in "siunitx"? If that is all it takes to tag a user, I had misplaced faith in the tagging algorithm.