Droid-Life has just confirmed what Justin's been hearing: that Verizon's network is having issues. Apparently both 3G and 4G are affected, and Thunderbolt activations are also reportedly being held up. No word on what the issue is or what areas are affected, but Droid-Life has asked readers who are experiencing issues to drop a line with the details in the comments, so that would be a good place to check.
Justin Case and TeamAndIRC have been fielding complaints/accusations/questions from angry rooted Thunderbolt owners who think their root method may be to blame. Don't worry - that's not the case; your rooted Tbolt has nothing do with it. It's simply a network issue that should (hopefully) be fixed in short order.