I wonder, why
! symbol is called exclamation mark, but
= symbol is called equal sign? Is it only tradition or there is something behind?
I cannot comment yet, as my karma will not allow it. The exclamation mark was referred to as “sign of admiration or exclamation” in the 15th century according to http://en.wikipedia.org/wiki/Exclamation_mark
I think it is just convention.
If you think about the = sign, you can argue it "marks" equality. On the other hand, if you use "exclamation sign", in my mind, the street sign pops up.