I am confused to say the least :S

Yes, you should. That person now has your Steam username and password.

It's probably The Ring girl, lol.

i really hope you didn't store your credit card data in steam...

Nah. it's just a stalker freak who now knows where you live ^^ no need to be worried :p

I remember once on a mmo game.. A guy with a weird nickname, probably a chinese, gave me a lot of items and money, then said me bye and disconnected.

Hmm sounds a bit strange, but I wouldn't be too worried. After all, he didn't try to scam you or anything. Maybe he just randomly added you because he though you're cool or have a nice avatar or something, but didn't expect you to contact him. Then he got flustered from you contacting him and he decided to take some distance. I don't know, people who add you randomly can be a little weird sometimes. :I

Once i got a similar friend request:
I: hi
He: hello
He is now offline
Maybe we scare people :(

probably wanted to 1v1 you on civ

Maybe he added the wrong account (like a wrong number dialed)?

I had someone add me to ask if I spoke french, he didn't remove me, but when I said no he said "ok" and never replied again

maybe he was trying to find some another person and he add u and then he realise that you are wrong person ? :D

You have seven days.

yes, you have to worry. From now on you're marked as an enemy. Beware, tonight aliens will come and take you.

Aliens.
Or...

You have seven days.

sorry if I don't get all of the ring references, I can't remember anything about that film XD

Hats

maybe he thought you also spoke japanese and was disappointed to see so much english from you

its because you are scary man D:, that is why we dont see each other anymore after......that day "memory filter"

it was a ninja
he sliced ur throat but your head had not parted with your body yet.

beware: go gather all that tape u have in the garage!!! D: