Although this is true, the item giveaway probably did not affect the results of the Valve hardware survey. For this to happen, those VM users or temporary users would have had to have been on it at the time of the survey, so the numbers we see are likely genuine adopters.

> The last time they did this, for users who logged in from a Mac, the promotional item became a kind of in-game de facto currency.

FWIW, this won't happen again, as the Tux items are not tradable.

They're likely to become tradable soon as the promotion is now over and other promotional items become tradable after their promotion is over.

Still, I personally doubt they'll be worth much unlike the Ear Buds you got from playing on a Mac purely because at the time trading didn't exist. So no one went out of their way to get them, leaving only the people who actually had Mac with them, making them highly sought after because there's only so many of them. Not to mention it's outside of most peoples knowledge to run an OS X virtual machine. While with this Linux item its been expected to be worth a lot and making a Linux virtual machine is relatively a simple task, meaning now there's a lot more Tux's to go around.

A similar thing to the Ear Buds also happened with a promotional item for "Sam & Max: The Devil's Playhouse" in the past called "Max's Severed Head" (http://wiki.teamfortress.com/wiki/Max%27s_Severed_Head) which rocketed in price when trading became available due to the fact there's a limited amount of them and they don't randomly drop while playing. They're currently worth around 26 keys which is ~£50 if you buy the keys directly from the store, but keys can be found cheaper and the price of course changes all the time.