Creston wrote on Jan 20, 2015, 00:58:
And obviously I refuse to log my Steam credentials into some unknown website (And I pity the poor suckers who do.)
It uses Steam's open ID system so it should be as secure as the rest of Steam.
From steamcommunity.com (Valve's site, not SteamLeft's):
By signing in through Steam, steamleft.com will be able to identify you within the Steam Community and retrieve your public gameplay information (such as stats and achievements).
Steam will not reveal your username or password to this site, rather a unique numeric identifier will be shared. You should never enter your Steam login credentials into a third party website!