Regarding your related question, the engine automatically deletes abandoned accounts.
When is it safe to declare an account abandoned? We came up with these two rules of thumb. If..
- the user has not visited the site in six months AND
- the user has not done anything of significance, ever
.. their accounts are effectively abandoned. With that in mind:
if the user has not visited the site in six months AND
the user has not done anything of significance, ever .. their accounts are effectively abandoned.
We delete cookie-based unregistered accounts when:
- The user has not visited Stack Overflow in six months AND
- The user has less than 50 reputation, and no visible (not-deleted) posts
We delete OpenID registered accounts when:
- The user has not visited Stack Overflow in six months AND
- The user has only 1 reputation, no visible posts, and no other accounts on the network
Why this shouldn't be added
Every once in a while a user comes up with a way to make something important more clear to new users (because, let's face it, the new users are the ones that are causing all the chaos)!
As you've already pointed out, the information we're talking about is available through the users profile. So what we're talking about here would essentially mean putting the information next user info container shown next to each post or adding some sort of notification before, during and/or after the user writes the comment.
The first option is off the table right away, because we don't want to clutter the user info box with an information like that. It's simply not important enough and the user probably wouldn't understand it either, unless it's a full sentence.
The second option is also bad, because, believe it or not, new users aren't really in the habit of reading. They prefer writing!
New users already get a notification when writing their first answer which should tell them about how to properly answer a question (because, very often, they aren't actually answering anything). New users love to skip that notification, because, hey, this is a forum and they know how to use a forum!
So we would add a notification that's only relevant to a very small fraction of the users that visit the site, because:
they have to have 50 reputation to comment
but they still haven't figured out how to check if someone doesn't use the site any more
and they have to care about that information enough to have an impact on their desire to post the comment
I would claim that this is a very small group of people. If something is only relevant to a very small group of people, we don't need it cluttering up the website.
Why this won't be added
Sadly, I really have no say at all when it comes to what feature will be added to the site and your suggestion is as good as mine. So my personal opinion, as stated above, has really no relevance when it comes to the decision if we'll get this implemented.
However, I am fairly certain that we won't see this feature implemented regardless.
"The team" is already focused on improving the site in various to make it easier for new users to get a grip on things. We see this in the new closing system and/or the new help center. Changes that only impact a small amount of users have such low priority that they're probably not worth the effort.