The United States has now elected a President who has pledged universal broadband. On almost the same day, AT&T announced it would be following some of its fellow network operators into trialing metered broadband.

Broadband caps have been much more common in Europe, but the trend there is away from caps, not towards them. Caps stifle innovation, discouraging the development of richer Internet experiences and the convergence of voice and video with data.

AT&T’s proposed caps start at 20 GB of data transfer per month. That’s equivalent to about 64 kbps of sustained data — barely the kind of speed a modem can manage. Or, put another way, that’s five 4 GB, DVD-quality movie downloads. And those caps are generous compared to Time Warner’s — AT&T proposes 20-150 GB caps, vs. TW’s 5-40 GB. (Comcast is much more reasonable, with its 250 GB cap.)

The US already has pathetic broadband speeds compared to much of the rest of the developed world. There are lots of good reasons for that, of course, like our broader population spread, but we don’t want to be taking steps backwards, and caps are certainly that. (And that’s not even getting into the important question of what “broadband” really constitutes now, and what, in a universal deployment, should be the minimum speed necessary to justify the infrastructure investment against future sustainable usefulness.)

Yes, network operators need to make money. Yes, someone has to pay for the bandwidth. Yes, customers with exceptionally high bandwidth usage should expect to pay for that usage. But the kind of caps that are being discussed are simply unreasonable, especially for a world that is leaning more and more heavily towards video.

A few months ago, comScore reported video metrics showing 74% of the US Internet audience watched video, consuming an average of 228 minutes of video. 35% of that was YouTube, so let’s call that 320 kbps. It looks like the remainder is mostly higher-quality. Hulu makes a good reference — 480 kbps – 700 kbps, with the highest quality topping 1 Mbps. For purposes of calculation, let’s call it 700 kbps. Add it all up and you’re looking at about 1 GB of content delivered to the average video-watcher.

Average page weights are on the rise; Keynote, an Internet performance measurement company, recently cited 750k in a study of media sites. I’d probably cite the average page as more in the 250-450k range, but I don’t dispute that heavier pages are where things are going (compare a January 2008 study). At that kind of weight, you can view around 1500 pages in 1 GB of transfer — i.e., about 50 pages per day.

A digital camera shot is going to be in the vicinity of 1.5 MB, but a photo on Flickr is typically in the 500k range, so you can comfortably view a photo gallery of five dozen shots every day in your 1 GB.

Email sizes are increasing. Assuming you get attachments, you’re probably looking at around 75k per email, as an average. 1 GB will let you get around 450 emails per day, but if you’re downloading your spam, at the 95% mark, that gets you about 20 legit messages per day.

If you’re a Vonage customer or the like, you’re looking at around 96 kbps, or around 45 minutes of VoIP talk time per day, in 1 GB of usage.

Now add your anti-virus updates, and your Windows and other app software updates. Add your online gaming (don’t forget your voice chat with that), your instant messaging, and other trivialities of Internet usage.

And good luck if you’ve got more than one computer in your household — which a substantial percentage of broadband households do. You can take those numbers and multiply them out by the number of users in your household.

A 5 GB cap is nothing short of pathetic. Casual users can easily run up against that kind of limit with the characteristics of today’s content, and families will be flat-out hosed. With content only getting more and more heavyweight, this situation is only going to get worse.

20 GB will probably suffice for single-person, casual-user households that don’t watch much video. But families and online entertainment enthusiasts will certainly need more, and the low caps violate, I think, reasonable expectations of what one can get out of a broadband connection.

Making users watch their usage is damaging to the entire emerging industry around rich Internet content. I respect the business needs of network operators, but caps are the wrong way to achieve their goals, and counterproductive in the long term.