Bliz will never ask for you to goto any website via an in game whisper. If there was anything they needed to contact you about it would be via your registered email and it would also include your game name and real name or the name you signed up with. Also worth to always take note of the spelling "that person used Blizzardd" and the website in question he/she was wanting you to goto. Blizzard will always send the link in the email and it will always be battle.net not Battle.net.tk or anything ending in .tk