If you're clinging to your grandfathered Verizon unlimited data plan, here's some bad news. Starting October 1, Verizon will throttle LTE speeds for heavy data users who enter high-volume areas. As GigaOm points out, this means Verizon will privilege users who pay for their data per gigabyte over their customers who use unlimited plans. And this means your data service is going to fall apart in certain areas if you're on an unlimited plan and you're in the top five percent of data users.
Verizon still offers unlimited plans to people existing customers who signed up for them before the company realized they weren't nearly as lucrative as data plans that have ceilings. Verizon hasn't kiboshed unlimited outright, but this kind of move shows that they have no interest in making it easy to keep one.
Again, only five percent of Verizon's unlimited users will be affected, so for most people still on the plans, it's no big deal. That means you'll be okay unless you use over 4.7 GB of data each month, which is a lot, and even then only in areas that are already congested. If you do use that much: What are you doing on your phone? And... do you not have Wi-Fi? [GigaOm]