iPhoto location compatibility?

Does the iPhoto location tags only work with other user's of iPhoto?

I have been mailing pictures from iPhoto via mail to a PC, with the location enabled option ticked, only to be told no location is found at the recipients end.

In this case it was a gmail address o a PC with Vista, they could see the pictures but there was no way of knowing the location. The pictures have the location info at my end in iPhoto.

I'm guessing that if I send them to another mail address on a Mac with iPhoto they'll get the location info as well?

What I'm saying is it just iPhoto to Photo Mac user's that can benefit from this?

Thanks in advance.

Could be. You can test this by dragging a correctly-labelled picture out of iPhoto and then using another program to examine the EXIF or IPTC data embedded in the photo. I use ACDSeePro for Mac for this (of course), but the point is that EXIF and IPTC data are readable across different programs and platforms, whereas some of the info iPhoto inputs is just written in a database that is only readable by iPhoto.