Recently, one of my clients asked me to program up a way to determine if a user exists on a server (in an e-mail sense) without sending them an e-mail (it's not a spammer, I promise! I get enough Viagra ads, don't really want to contribute to that.) Like a good little programmer, my mind raced to what was available: Finger and SMTP.
Now, I haven't had to do anything like this in years. Back when I last used finger, some e-mail hosts still implemented it. Now, it turns out that not a single one of the servers I tested support it.
So, HN, I ask you: whatever happened to finger?
Most users wouldn't want the ability for an unknown 3rd party to try to guess at, or verify, their contact info.