?repeats the group contents below at most once:
wwwthe literal text www (case sensitive) .any character (except for line terminators)
Negated Character Class[^@] @the literal @ (6410 / 1008 / 4016)
\w+any word character, repeated at least once
\.+the literal . (4610 / 568 / 2E16) , repeated at least once
\w{2,3}any word character, repeated between 2 and 3 times
g modifier: global. Finds all matches instead of stopping after the first