next unless $line =~ m{^(\S+) (\d+) (.*)};
  my ($site, $userID, $data, $data2) = ($1, $2, $3, $4);
  # you have 3 capturing paran's but you try to call $4
  # your 2 data columns get folded together in $3 because of your greedy .*

  $user{$userID}{$site} = $data, $data2;
  # $data2 is useless and I think you are trying to use an array ref
  # but that is not what you are doing [ ] signifies an array ref