SpringPower: Now you have piqued my curiosity. How do other websites, regardless if it is gaming or not, do this?
Fenixp: When you log in from an unauthorized computer, they send you a randomized security code on your email which you also need to log in besides your user name and password to authorize the machine. All further log ins from that machine will work without the code. Basically, whenever you're accessing account from a new computer, the website also checks if you really are owner of email registered with that account.
How does it track that the computer is "authorized"?
At least on Steam, it seems I have to re-enter that damn code every damn time I want to enter the site through a web browser. Is it possibly using e.g. cookies to track it? I've set Firefox to wipe out all the offline crap (caches, offline data, cookies, history etc.) whenever I close the browser, as some sites use them for purposes I don't want them to (like limiting how many times per week I can access their pages, etc.), and also make sure all personal data (browsing history, saved passwords etc.) are also deleted when I close the browser. I wouldn't want e.g. my wife to enter different sites with my account just because I forgot to log out. Not to mention the case when I was able to access and read my friend's personal emails, just because he had used my PCs web browser to check them. That wouldn't have been possible if the browser had deleted all cached data when he closed browser.
I'm for GOG checking via email if you or someone else tries to change the account password (that just makes sense, and I am surprised if GOG doesn't so that already now). I'm against that "enter the code all the time" shit which is present in Steam.
Of course, in Steam it is now less important to me because I simply don't access their site with web browsers anymore. Only with the client (where I don't apparently even have an option to delete any tracking cookies automatically and whatnot). Fine by me I guess, as the client is not used for anything else besides accessing the Steam site.