It is possible that the Osama Bin Laden media obsession has caused you to miss this little tidbit, but on Monday AT&T officially killed uncapped internet. The much talked-about data limitations officially went into effect without too much backlash hitting the interwebs.

As a quick reminder, AT&T DSL customers will now be charged penalties for exceeding a 150 GB limit per month. For every 50 GB of additional data, users will be charged $10. UVerse users’ cap is set at 250 GB.

These data restrictions have already been in place if you have Comcast, who limits broadband users to 250 GB per month. Although true that many users don’t come anywhere close to 250 GB per month, 150 Gb is a different story. Heavy users who, let’s say, watch a lot of streaming video through Netflix and download a lot of media could surpass this limit in a month’s time.

The data cap implementation news has not been lost on two prominent policy groups, The New America Foundation and Public Knowledge. They have written a joint letter to the FCC asking that they investigate the motivations behind these caps.

In light of the fact that 56% of American broadband subscribers’ connections are restricted by some sort of broadband cap,1 Public Knowledge and New America Foundation’s Open Technology Initiative urge the Bureau to exercise its statutory authority to fully investigate the nature, purpose, impact of those caps upon consumers.2 The need to fully understand the nature of broadband caps is made all the more urgent by the recent decision by AT&T to break with past industry practice and convert its data cap into a revenue source.

The letter continues to single out AT&T, mostly for the fact that their 150 GB data limit seems motivated simply by profit, as it is unlikely that it would be an issue of volume incapabilities.

In the world of broadband data caps, the caps recently implemented by AT&T are particularly aggressive. Unlike competitors whose caps appear to be at least nominally linked to congestions during peak-use periods, AT&T seeks to convert caps into a profit center by charging additional fees to customers who exceed the cap. In addition to concerns raised by broadband caps generally, such a practice produces a perverse incentive for AT&T to avoid raising its cap even as its own capacity expands.

Furthermore, it remains unclear why AT&T’s recently announced caps are, at best, equal to those imposed by Comcast over two years ago. The caps for residential DSL customers are a full 100GB lower than those Comcast saw fit to offer in mid-2008. The lower caps for DSL customers is especially worrying because one of the traditional selling points of DSL networks is that their dedicated circuit design helps to mitigate the impacts of heavy users on the rest of the network. Together, these caps suggest either that AT&T’s current network compares poorly to that of a major competitor circa 2008 or that there are non-network management motivations behind their creation.

The two groups ask that the FCC monitors a few points, such as the relationship of enforcement to times of network congestion, when and how often penalties are paid and how AT&T arrived at their specific limits.

“Broadband internet access is critical to the continued economic and cultural prosperity of our nation,” they say,

Amen. Although for some, data caps are unforgivable in principle, if these caps start affecting more American internet users, I’m sure there will be more than policy organizations writing letters.