This should work for bitshares.org domain and pass your referral to bitshares.org/wallet.
One of the reasons it didn't work for
@tonyk might be a browser's cache - I've added a tracking code to bitshares.org not so long ago, so if page was cached it couldn't pass you referrals. The other possible reason could be related to issues passing cookies via CORS ajax requests in some browsers, will check this out..