Why did I get a bunch of items from just logging in?

I logged into TF2 for the first time in about 6 months today and received almost 15 items, mostly genuine, upon arrival. I was under the impression that you needed to spend time in game in order to earn items. I'm not complaining, but why did I get them and how (if possible) can I replicate this?

PS: I can provide a list of the items I got when I get home in a few hours.

Solution 1:

Genuine quality items are obtained only as promotional items from purchasing other Steam games. Most likely you purchased a few games during that time and didn't realize there was a promotional item involved.