My curiosity side agrees with you, but my practical side does not.
> He says passwords were "hashed and salted." This could be anything from the naïve MD5(pass+salt) to the more secure bcrypt or PBKDF2. Now, I have every reason to believe that Valve is smart enough to not use methods like the first, but information is always welcome in a scenario like this.
Do these details actually matter to you, a technically savvy user? If they told you they used bcrypt or PBKDF2 for their password hashed and salted passwords would you think to yourself: "oh well, in that case I don't need to change my password" or are you going to take the few moments and change you password anyway? I'd probably just change my password.
For even less savvy users, they're getting technical details that they don't really care about now. Depending on where those details are in the message they might miss important bits of useful information.
I suppose if they said it was MD5(salt:pass) and you used the same password for steam and something else you might have reason to be concerned, but probably not unless they are targeting you specifically.
That said, I think any company should provide a link to a blog that does dig into the important technical details for people that want to know. And keep updating it as new information is found.