I found this one at “Ask Yahoo!” … and since it fits “my” quotes too (I guess), I thought I’d write it here:
“Sic” is Latin for “thus.” Yeah, that didn’t clear it up for us either. But apparently, since the 1880s, writers have used [sic] next to quotations that include errors.
This little notation means, “Hey, I know this quote looks wrong, but it was that way when I found it, so don’t blame me.” Maybe the original text used archaic spelling or the original writer just messed up. But the person who’s quoting that text is aware of the earlier mistake and wants you to know it.
[Sic] is shorthand for all that, at least to scholarly types.
Btw. To my knowledge, all the quotes on this site are correct! But bear in mind that a lot of the quotes were originally written in another language, so details might have got lost in translation.