GigaOm has a helpful guide to current conspiracy theories that attempt to explain why so many underseas cables are getting severed.
The big problem with all the theories is that if Evil Entities are targeting specific countries, then why would they want to damage multiple other countries too? Then there’s the little factoid that no ships were in the area where two of the cables were cut. (AHA, you say, that just proves how Devious They Are. The fiends must be using submarines, then… Hmmm, but to reiterate, why?)