Why is the word '$$$$$' being censored?

[MindBomber]

I noticed today the word $$$$$ is censored.

I don't understand why such a mundane and common word would be censored by the forum, can some explain why?

The word I'm referring to is below..

T
r
a
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k

[jtanner_]

I would imagine its because of a certain shop who isn't a sponsor. Kind of silly if that's the case though.

[belaud]

probably fast$$$$$?

[?NR]

it's temporary.

and yes it is due to spam. I chose not to ban this instance, just a subtle hint.