well for the lazy ones, here is why:

"All BlackBerry services fall within the UAE regulatory framework developed by the TRA since 2007, however because of BlackBerry's technical configuration, some BlackBerry services operate beyond the enforcement of these regulations, the TRA stated.

BlackBerry data is immediately exported offshore, where it is managed by a foreign, commercial organisation. BlackBerry data services are currently the only data services operating in the UAE where this is the case.

Today's decision is based on the fact that, in their current form, certain BlackBerry services allow users to act without any legal accountability, causing judicial, social and national security concerns for the UAE."

pasted from the op link