Yes if you sign up now for unlimited data you will be grandfathered in, but anyone that signed up after Feb 3rd of this year is subject to Verizons throttling policy. This is a quote from their web site regarding the new policy.
"If you subscribe to a Data Plan or Feature on February 3, 2011 or after, the following applies:
Verizon Wireless strives to provide customers the best experience when using our network, a shared resource among tens of millions of customers. To help achieve this, if you use an extraordinary amount of data and fall within the top 5% 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."
Here is the link for the above quote:
https://ecache.vzw.com/imageFiles/Myacct/nda/images/docs/VerizonWirelessServiceInformation.pdf
Verizon doesn't say what the cutoff point is that will trigger throttling, but from many reports its around 9gb on the 3g network. Since Verizon doesn't state officially what the number will be, it's safe to say it will be a moving number based on capacity issues. In other words while it's 9gb now, it could be reduced to much lower figures in the future - maybe something on the order of 2-3 gb like Tmobile or AT&T.
At the moment the 4g network does not seem to be throttled as I have read reports of people doing up to 30gb in a month with no slowdowns or throttling. Of course I am sure in the future as more 4g phones become available and more people start using 4g that Verizon will also start to throttle 4g, unless of course you are one of the lucky ones that had a unlimited plan in effect before Feb 3, 2011.
Facebook
Twitter
Instagram