cocoaforge

I only use AIM and MSN, so I can only speak for them, but:

In MSN, whenever a friend sends me a link with a link break following it, whenever I click the link it is opened with "%3Cbr%20/%3E" after it. This doesn't happen with AIM.

Relatedly, I wasn't able to open any hyperlinks a friend sent me through AIM.

The second one: I have it too

The person doesn't add the http:// prefix, so it goes somewhere else

Just copy the address, and edit it in the address bar in Safari or whatever you use

Could you paste an example of a link which wouldn't open when sent over AIM?

That's a new MSN bug, duly noted.

A link: [url=file:///Applications/AdiumX/SVN/Adium.app/Contents/Resources/Message%20Styles/Smooth%20Operator.AdiumMessageStyle/Contents/Resources/xanga.com/NastyRanger]ducky world[/url]

My friend sent me that link. The URL that I copied was this:
[url]file:///Applications/AdiumX/SVN/Adium.app/Contents/Resources/Message%20Styles/Smooth%20Operator.AdiumMessageStyle/Contents/Resources/xanga.com/NastyRanger[/url]