From Facebook Developer Wiki

Comment from Matt Hamer (22nd September 2008):

Note that at present this tag will not yet work because:

"Starting today, we are beta-testing this technology and policy change with a very limited set of companies. We plan for this policy change to take effect officially before the end of September, based on a successful beta period and rollout. If there are any changes or updates to this plan and timing, we will inform you quickly." (Facebook Developers' Blog)

Update at: 06 October 2008. Tags are now functioning. Some non-through testing shows the Location parameter appears to work correctly. I do not have my birthyear entered on Facebook. An "18+" age paramater returned as false in my case, when in fact I am over 18.

Question: Does this tag even work in Static FBML apps for Pages? --1517862561 10:01, 12 June 2009 (PDT)

This tag won't work, but you can edit the settings for your Page to restrict it to particular ages or countries. Pete (563683308 15:16, 10 September 2009 (PDT))

this tag fb:restricted-to is not working in any way, could some body help me?

Please file a bug and describe the issues you're having and include the code you use to reference the tag. Thanks, Pete (563683308 14:42, 10 September 2009 (PDT))