There was little sign of the Obama campaign's vaunted world's largest phone bank at Invesco Field at Mile High on Thursday night, but the campaign did manage to score a few points by asking attendees to whip out their cell phones. According to Obama's Colorado campaign chair Ray Rivera, a contest that asked those at the event to text in a message of support to 62262 (which, naturally, spells "OBAMA" on a standard keypad) net the campaign tens of thousands of cell phone numbers in a matter of a few hours.

Early in the evening at Invesco, Rivera pointed to a map of the U.S. on the JumboTron and called on all of us sitting in the stadium to pull out our mobiles. Every text message sent in would be attached to a state, via area code, and the start marking on that state would grow ever larger as the texts poured in. "Let's light up the map and let's light a path for America's future," Rivera cheered. "Tonight we're going to do some work." The "work," of course, was really less a matter of volunteer labor than it was a way to accumulate mobile numbers for the campaign.

Still, the "work" worked. Rivera came on stage a few hours later to announce that the campaign had collected more than 30,000 cell numbers.

Now, the early estimate for the Invesco rally was that it would attract some 75,000 supporters -- twice the number of people that fit into the Pepsi Center each night. And as the day wore on, there seemed to be few empty seats in the house -- mostly just a few in the nosebleeds up top. Importantly, much of the crowd was made up of people attending on Community Credentials, which was a program designed to open up the convention to volunteers, especially those from Colorado.

Why such an interest on the part of the Obama campaign in attracting so many locals to Invesco? In part, because Colorado is a hotly-contested state, and the Obama campaign is fairly salivating over its nine Electoral College votes. Some measure of those cell numbers, then, are connected to incredibly valuable supporters (and, by extension, to everyone in their address books) in that battleground state. Indeed, Colorado's "star" was among the largest on the map.

As Garrett Graff recently pointed on in the New York Times, Obama's texting program -- from the VP announcement to the JumboTron contest at Invesco to SMS-based trivia that also scrolled on the big screen Thursday night ( "How large would Senator Obama's tax credit for college students be? Text E4 to 62262 for $1000...") -- has a far larger purpose beyond giving supporters an easy way to hook into the campaign: it gives the Obama campaign a database of cell numbers that might prove to be electoral gold when it comes to turning out critical voters from Boulder to Aspen, come election day.