Is it possible to link players in sitemail?  If so, would someone be able to explain how?  Thanks.

Ctrl-C (copy) to the address at the top of the player's card. Ctrl-V (paste) into the text of your sitemail.  Keep in mind, they'll only see current rantings for a player unless they're logged into your world at the same time.

They may have to do their own copy/paste into their own browser.  I don't know if sitemail will automatically turn that into a link.

It doesn't.