function linkify($text){
//links
$text = preg_replace(
'@(https?://([-\w\.]+)+(/([\w/_\.]*(\?\S+)?(#\S+)?)?)?)@',
'<a href="$1" title="" target="_blank">$1</a>',
$text);
//hashtag
$text = preg_replace(
'/\s+#(\w+)/',
' <a href="http://search.twitter.com/search?q=%23$1" title="Search on twitter for #$1" target="_blank">#$1</a>',
$text);
//users
$text = preg_replace(
'/@(\w+)/', '<a href="http://twitter.com/$1" title="$1 on twitter" target="_blank">@$1</a>', $text);
return $text;
}