The link below looks and feels like a link to Microsoft.
Even when you are on top of it with the mouse cursor, the status bar will show www.microsoft.com, even on a fully patched WinXP SP2.
Actually, it is a link to www.itzhaki-weinberger.com.
Demonstration of exploit written by Paz Itzhaki-Weinberger, October 2004
Malicious websites or malicious email creators can use such a page to create innocent links users will trust, although they will lead to a malicious webpage.
Conclusion? BEWARE! do not click any link from unknown origins, even if it looks okay to you!