Try sending a TinyURL link to your friend. You would get a message “The following message could not be delivered to all recipients:” Microsoft has recently banned sending these URLs on Windows Live Messenger at the time when GTalk has taken away most of its chat users.
It is reported that TinyURL has more than 1.5 billion hits every month. TinyURL helps make long URLs shorter and easier to send through email. TinyURL has become largely popular and there have been reports of spamming as spammers send malicious site links in the form of TinyURLs.
However, none of the popular messengers have blocked URLs from TinyURL. Microsoft has blamed its third-party partner who handles spam and URL blocking.