In the continuing saga of Microsoft taking all prior internet standards and pissing on them before tossing the out the window entirely, I just stumbled across one involving Exchange servers (the email servers Microsoft markets).
Let's say I have an email account on my company's exchange server, call it email@example.com. Let's say also that as a convienance for internet email, my company offers shortened email addresses, so I can have my reply-to address be firstname.lastname@example.org, which looks much cleaner. Now, let's say that I accidentally typoed my reply-to address as email@example.com (yes, a really bad typo, but stick with me here). Now, let's say there's someone else in my company by the name of bob. Bob also has an email account on the same server as me (it's all the same company, so this is actually very likely to happen). Now, assume Bob has a friend who works for an entirely different company that has a very similar name, and their emails all have @company.org as the address. Let's go one step further and say that Bob's friend is also named lograh, so his friend's email is firstname.lastname@example.org (it could happen).
Now, asside from the fact that when people go to reply to my email, Bob's friend will get their replies instead of me (a problem that is my fault), there's another problem here that's microsoft's fault. See, when Bob goes to send his friend an email, the company exchange server will see that it is addressed to "email@example.com", it will say to itself "hey, *I* have a user named lograh, and I know that his reply-to address is firstname.lastname@example.org, so I'm going to just send this email to him instead of handing it off to company.org!".
You see the problem here? Microsoft, in their infinite stupidity, have decided that rather than have their email server actually send off the email to where it's actually *ADDRESSED*, their server will simply decide to give it to anyone who has a reply-to address equal to the "to" address for that email!.
I'm going to do a little more testing to see just how far it will go, but I'm thinking this could cause some problems (allready has with one of my users).
Also, if someone can find prior evidence that this type of idiotic server behavior *is* actually the standard, please inform me.