Here's the initial note from the forum. I copied it before and can't reload, so I don't know the user that posted it.
"During a shared library update distributed to our hosts, a number of the hosts incorrectly have marked Linodes as being shut down. To recover from this we may be issuing host reboots to upgrade their software to our latest stack, and then bringing the Linodes to their last state. We're working on this now and expect to have additional updates shortly. We'll also be notifying those affected via our support ticket system. Please stand by."
Mine is also at Dallas (dallas98) but has only been up for ~20 minutes and is extremely slow.
edit: Looks like my VPS was offline for 20 ~ 30 minutes and has settled down now.
My vps is still up and has been up (at the dallas datacenter) and seems to be working fine.