You could just say, hey it's the same website, the same people behind each , the same Will Hill.
But it's not.
Williamhillpoker is just a pure skin of Titan Poker - whereas poker.williamhill is the good one ! ; same thing between casino.williamhill and williamhillcasino .
Be careful so - it seems that the William Hill "merger" into playtech has made some very misleading casino (and poker) skins names...