Çektiğin verileri bir diziye at ve array_unique fonksiyonunu kullan.
Son söylediğini anlamadım.

Örnek;
<?
$degisken="
http://www.site.com//showthread.php?t=10014
http://www.site.com//showthread.php?t=10014
http://www.site.com//showthread.php?t=10014&amp;page=2
http://www.site.com//showthread.php?t=10124
http://www.site.com//showthread.php?t=10089
http://www.site.com//showthread.php?t=1462
http://www.site.com//showthread.php?t=1462
http://www.site.com//showthread.php?t=1462&amp;page=2
http://www.site.com//showthread.php?t=1462&amp;page=3
http://www.site.com//showthread.php?t=10036
http://www.site.com//showthread.php?t=9848
http://www.site.com//showthread.php?t=9848
http://www.site.com//showthread.php?t=9848&amp;page=2
http://www.site.com//showthread.php?t=9634
http://www.site.com//showthread.php?t=9634
http://www.site.com//showthread.php?t=9634&amp;page=2
http://www.site.com//showthread.php?t=9634&amp;page=3
http://www.site.com//showthread.php?t=9634&amp;page=4
http://www.site.com//showthread.php?t=9611
http://www.site.com//showthread.php?t=9611
http://www.site.com//showthread.php?t=9611&amp;page=2
http://www.site.com//showthread.php?t=9518
http://www.site.com//showthread.php?t=9423
http://www.site.com//showthread.php?t=9423
http://www.site.com//showthread.php?t=9423&amp;page=2
http://www.site.com//showthread.php?t=9423&amp;page=3
http://www.site.com//showthread.php?t=9174
http://www.site.com//showthread.php?t=9174
http://www.site.com//showthread.php?t=9174&amp;page=2
http://www.site.com//showthread.php?t=9174&amp;page=3
http://www.site.com//showthread.php?t=9174&amp;page=6
http://www.site.com//showthread.php?t=9358
http://www.site.com//showthread.php?t=9273
http://www.site.com//showthread.php?t=9273
http://www.site.com//showthread.php?t=9273&amp;page=2
http://www.site.com//showthread.php?t=9331
http://www.site.com//showthread.php?t=9209
http://www.site.com//showthread.php?t=9209
http://www.site.com//showthread.php?t=9209&amp;page=2
http://www.site.com//showthread.php?t=9209&amp;page=3
http://www.site.com//showthread.php?t=9233
http://www.site.com//showthread.php?t=9235
http://www.site.com//showthread.php?t=9235
http://www.site.com//showthread.php?t=9235&amp;page=2
http://www.site.com//showthread.php?t=9235&amp;page=3
http://www.site.com//showthread.php?t=9213
http://www.site.com//showthread.php?t=9213
http://www.site.com//showthread.php?t=9213&amp;page=2
http://www.site.com//showthread.php?t=9203
http://www.site.com//showthread.php?t=6041
http://www.site.com//showthread.php?t=6041
http://www.site.com//showthread.php?t=6041&amp;page=2
http://www.site.com//showthread.php?t=6041&amp;page=3
http://www.site.com//showthread.php?t=6041&amp;page=11
";

$dizi=explode("http://",$degisken);
$dizi=array_unique($dizi);

foreach ($dizi as $link) {
echo "http://".$link."<br>";
}
?>