Nice for a first modification

I'd suggest the following change so it doesn't clash/break other mods:
Code:
$hook_query_joins = "LEFT JOIN " . TABLE_PREFIX . "postinfo AS postinfo ON (post.postid=postinfo.postid)";
$hook_query_fields = ", postinfo.browser AS browser, postinfo.OS as OS";
To:
Code:
$hook_query_joins .= "LEFT JOIN " . TABLE_PREFIX . "postinfo AS postinfo ON (post.postid=postinfo.postid)";
$hook_query_fields .= ", postinfo.browser AS browser, postinfo.OS as OS";
Basically change = to .=