Zakat goes to all sorts of purposes. One of them is to get poor, destitute non-Muslims to convert to Islam, as explained in the post linked below on Money Jihad blog.
The gist of this is that when a Western financial institution facilitates Shariah Finance it is subsidizing the promotion of Islam and Shariah. That is the whole purpose of Shariah Finance.
http://moneyjihad.wordpress.com/2012/04/08/zakat-used-in-ethiopia-to-bribe-christians-to-islam-2/
