Personally, that's an command that I never use; not sure how popular it is with the Windows userbase in general.
In XP, there's a folder that you can put folder and program shortcuts in, that will populate the send to menu. In fact, this essentially is my quicklaunch method when using XP. Just put a link to notepad2 in there, and you can view anything in ascii. Rinse and repeat.
It's so useful in fact, that they might have been able to bring it into wider usage, and maintain continuity with older Windows, by adding a context menu such as 'Make me a send to place', which would add a shortcut to the clicked folder or application into the send to menu.
To me on OS X, the Finder sidebar and Dock are the rough equivalent. 90% of my Finder work is selection and dragging to the sidebar, or Dock, the same thing I would use send to on Windows for.
The "send to" email, however: I don't think you can use it with any web-based email, correct? Do people usually have Outlook set up on their machines these days?
There's one more: if you have a bluetooth adapter (or a laptop with embedded support), it shows a 'Send to Bluetooth device'. I find this very useful for sending files to my phone.