qq has the same effect of double quotes. It may be used to tell perl to work as if the string inside the qq range is enclosed with '"'. The difference is that the charecter immediately following qq will be the delimiter, instead of '"'. You can use nearly anything that's not whitespace. If you use some kind of embracing character, such as '{', '[', or '(', then you have to close with the relevant closing brace.
More operators such as qq are discussed in perlop, as was referenced by broquaint. To list a few:
q - same effect as using single quotes (')
qw - break words to a list (qw(foo bar) == ("foo","bar");)
-nuffin
zz zZ Z Z #!perl | [reply]
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