Verizon Wireless will begin throttling the data speeds of customers who use an "extraordinary amount" of data, according to a document posted on the company's Web site.

First reported by BGR.com, the PDF on the Verizon site says the new rules will not affect the majority of the company's customers. However, if you are a heavy data user, you should be aware that your speeds will drop.

"If you use an extraordinary amount of data and fall within the top 5 percent of Verizon Wireless data users we may reduce your data throughput speeds periodically for the remainder of your then current and immediately following billing cycle to ensure high quality network performance for other users at locations and times of peak demand," states the document.

Verizon said it is taking the steps "to ensure that the remaining 95% of data customers aren't negatively affected by the inordinate data consumption of just a few users."

The company doesn't say how much data constitutes an "extraordinary amount," only that the new rules will affect the top 5 percent. Theoretically, that means you could be affected one month, but not the next even though you consume the same amount of data.

In addition to throttling data speeds of some users, Verizon also described new "optimization and transcoding technologies" it is implementing in its network to deliver files more efficiently.

Verizon began accepting preorders for the iPhone today and even reportedly asked its employees to delay ordering the phone because it anticipates "unprecedented" demand for the device.