What does swag mean in "Community Milestones Notifications about bounties, reputation and more. Hint: sometimes involves swag"?
"swag" is branded memorabilia that Stack used to give out at times. For instance, I have a t-shirt with the Science Fiction & Fantasy Stack Exchange logo on it, and a hoodie with the Super User logo... there's been a lot of swag given out over the past few years. There used to be contests here on Meta and the winners would get a swag package in the mail. Also, any user who reached 100,000 reputation or 250,000 reputation on a Stack Exchange site would get a swag pack as a token of appreciation for the work they've put in to the site.
However, as of recently Stack Exchange has put swag on hold because of cost reasons:
Unfortunately, we are no longer able to promise swag for any activities on our site. That covers spontaneous contests which aren't sponsored, as well as the swag for 100k and 250k milestones.
The amount of money we were throwing around to send someone a $15* t-shirt was a bit insane, and we cannot keep doing that. Without getting into specific financials, we can say that the hassles of international shipping were a huge financial burden and while our new swag vendor was able to drastically cut other costs, this was not one that we were able to get rid of.
So at the moment, there is no swag going out to users, unfortunately.