No

On the forums? Yes.
As a giveaway? No.

Short answer: No.
Long answer: Oh god, please please please not another one.

Oh and forums is okay though. I have 3 sitting in my inventory I should just ditch.

Another fine addition to the Dota2 thread of shame.

I was expecting this to be one of those disguised giveaway threads.

Since everybody else already answered your question I'll give you this:

Read This First Before Doing Anything Else On SG

There's no reason to be rude, people.

Yes, it is possible to find the answer to this question if one does a good job of searching. No, it is not readily apparent to a new member, nor is there a detailed explanation given in the FAQ or general website information. I had this exact same question, myself, and it took me half an hour to find the answer on my own as to why I was unable to gift my copies on this site. Perhaps if there had been someone friendly on SteamGifts to explain it to me, I would have learned the answer more quickly and easily.

What is the theard number?

Well, you can post the key here like I do
EZQPL-LAW74-MX8PR (DOTA2 inside)