The overall security of the network is not really under threat, since 10 Terahashes per second isn't a mark reachable by any known network or supercomputer. This does highlight the risks to the bitcoin network at large associated with pool mining. Concentrating the mining to a single server for the purpose of income stability also creates central points of failure/attack. I don't mine in pools for this exact reason, and don't think anyone with any substantial hashing ability should do so. 10K small lights are harder to shoot out than a dozen really big ones.
This brings me to another point.. in a conversation with a colleague he said " What if IBM or some other entity with tons of computing power bring it online all at once?" He mentioned something on the order of "3 trillion teraflops/sec" or something that one company has.
I did some rough calculations of the TFlops of of all the vid cards encompassing 11Thash. I think I came to about 100,000 on our network.
I know that teraflops does not equate directly to hashing power, but I would like to know if anyone knows of the biggest competition to our network?