As we mentioned this summer, AT&T was slated to begin throttling data plans as of October 1 this year. Reports of throttling are finally beginning to surface as more and more users complain they have received this dreaded text message from AT&T: "Your data usage is among the top 5 percent of users. Data speeds for the rest of your current bill cycle may be reduced."

Those who subscribe to the carrier's 4GB per month plan will remain unaffected, although those customers are still liable for overage fees once they surpass their allotted data. One might believe that AT&T's stiff overage fees would curb would-be data hogs, but oddly, the far smaller 200MB and 2GB packages are subject to doubly punished with both fees and throttling.

AT&T never provided exact figures for how much monthly activity flags an account, but consumer complaints seem to happen around the 2GB per month mark. The company claimed the top 5 percent of downloaders consume 12 times the average bandwidth. The speed at which users are throttled is also unknown, but anecdotal user stories suggest "Edge-like" speeds.

Already rated as the worst carrier by Consumer Reports for the second year in a row, throttling does not seem to be generating any additional good will. One user says, "I'm only at 1.5gb in 11 days and I just got the message stating that I'm approaching the top 5%." Another person tweeted, "Not sure how 2.1 GB/month puts me in the top 5%, but seems like @att just warn of throttling once you go over their highest data plan..." and another at Cult of Mac quipped, "Screw the top 5%... WE ARE THE 95%!!!".

Analysts at J.P. Morgan estimate the average iPhone and Android user will utilize between 800 to 825MB per month. This is up substantially from previous estimates as media and content-rich sites continue to explode.

While AT&T will send customers a warning SMS as they near the end of their data plan's rope, subscribers can also quickly check themselves by dialing *3282# on their handset.