Before the iPhone 4 became available on Verizon Wireless, the nation's largest carrier informed its customers that it would begin to throttle the bandwidth of the top five percent of its data users sometime this year. Well, that day has come.

Verizon sent an e-mail to customers on Thursday, September 15, informing them that the "network optimization practices" has started: 

"Beginning 9/15, we will start identifying customers who meet these criteria and will expand to others in the base after customer communications are completed. Network Optimization Practices only goes into effect when an Internet or Smartphone device with an unlimited plan/feature falls into the top 5% of data usage and is on a congested cell site."

The top five percent of data users will be subscribers who use more than 2GB of data during a monthly billing cycle, says Verizon. It also wants people to know that it's not throttling data in the same way AT&T and T-Mobile are, because it is only slowing connections when users are on a congested cell site.

[via Apple Insider]