It is using PHP and MySQL on server-side, AJAX on client-side, the I can't detail it now.. I just think it cost like adsense and a few more. Is it possible to run it on shared server at first? how much visitors (CPU time, not matter about traffic) can be charged? Or dedicated server? that will cost $1000+ to buy zend platform and a lot of other software? Is there any way to save the cost? BTW, Which hoster you will recommend? Thanks!