# Tag “*~294”: what is it?

I came across this weird tag accidentally. SO claims there are 67488 questions tagged with it. Is it a bug or a feature?

The screenshot:

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Seems to be gone now. –  Tim Post Feb 8 '12 at 15:32
@TimPost Hm. I'm still seeing the thing on the Questions page in Related Tags. –  Costique Feb 8 '12 at 15:43
I see 2,626,020 questions tagged...o.O –  tombull89 Feb 8 '12 at 15:47
Another weird thing is that I cannot find the tag using search or filtering the Tags page. –  Costique Feb 8 '12 at 15:49
Possible duplicate: meta.stackexchange.com/questions/100841/… –  Costique Feb 8 '12 at 15:57
@Costique Yup, but I'm not inclined to close this, as this seems to be one of those bugs. Ya know, the kind that has been linked to Tourette Syndrome. –  Tim Post Feb 8 '12 at 16:01
@TimPost: I'm seeing this in my list as well... –  animuson Feb 8 '12 at 17:15
This is strange, I can't reproduce it. –  Tim Post Feb 8 '12 at 17:17
@TimPost It's still there for me, though. Its number of questions is fluctuating as if it's a real thing. –  Costique Feb 8 '12 at 17:21
Wait, reproduced, look at the related tags between SQL and Ruby On Rails (thanks @Fabian) –  Tim Post Feb 8 '12 at 17:22
@TimPost: I also notice that specific tag has a title="show questions tagged '*~294'" whereas all the other tags in that list have a title=""... –  animuson Feb 8 '12 at 17:25
@TimPost Yay! That's it. I wonder if there's a valid tag which has the exact same number of questions. Could a valid tag be renamed/aliased? –  Costique Feb 8 '12 at 17:31
Also found in the Tagged Questions for c++, which shows *~294 × 12836. –  KennyTM Feb 8 '12 at 19:58

We had a secret sub-domain that we used to test features required for facebook.stackoverflow.com and recently removed it.

This tag is just some stale data that will be purged in a few hours, after peak traffic.

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And you would have gotten away with it, if it weren't for us meddling kids! –  Tim Post Feb 8 '12 at 20:15
shakes fist angrily –  Jarrod Dixon Feb 8 '12 at 20:16
Thanks for fixing it. Yeah, Facebook is evil, it's that bad. –  Costique Feb 9 '12 at 4:34

I can't say why the tag was appearing in that list, but it seems to be a valid combination of wildcards. The * character is a client-side wildcard and ~ is a server side wildcard. The server-side wildcard has the additional restriction that you need at least 4 characters in your pattern or it will be rejected.

So what this tag pattern means is

*   :match anything client-side
~   :match anything server-side
294 :match 294


The last match is needed because of the server-side 4 character limit, if you remove the last character the pattern is rejected. If you use a number there that doesn't exist in any tag this part seems to be ignored entirely and you're left with a pattern that matches every question on the site.

For tag the client-side wildcard is automatically replaced by the server-side wildcard, so this pattern is equivalent to ~~294.

That this URL works is probably a feature, but this tag certainly shouldn't appear in any tag listings.

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Thanks for the explanation. Looks like a bug. I wonder where the number comes from. –  Costique Feb 8 '12 at 15:55