the above post is correct, starbucks will have a router that has a DHCP server that (as the above posts says) will assign IP's to computers that connect, also the External IP wont be the same as the Internal IP's set with the DHCP so the computers wont be accessable via the internet by thier local ip as the request exteranlly is to the router, if you wanted this functionality you can enable port forwarding and open a port for each computer but thats out of the scope of this post.

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mysql> SELECT * FROM `users` WHERE `users`.`clue` > 0;
Empty set (0.00 sec)