Okay, I'm incredibly new to trading, so maybe is something that i don't know, but anyway, i wanted to sell a Screaming Tiger Shred Alert and this guy sends me a friend request. I add him, i make him the offer and then bla-bla-bla. Then he asks me to deposit my item on the scrap.tf site inventory, for him to check the price, and so i (stupidly) did, thinking "Hey, i don't know why he wants me to do this, but he can't steal my items there, right? It's from a secure website, so nothing will go wrong!". Well, my item and some keys i had there all disappeard and he/she just unfriended me. I assume he got my items but I really don't know. If yes, is this a common method? I mean I know I was really really stupid, but how could he get my items this way?