OBAMA, SCARLETT JOHANSSON AND A FACEBOOK PRIMARY

Des Moines, Iowa -- Scarlett Johansson was the special guest at Barack Obama's last big rally in Iowa last night. The Obama Campaign avoided publicizing her appearance or involving her in the official program, but she spoke at a separate, small gathering to rally young voters.

Johannsson talks to young voters for Obama in Des Moines. For more, check out Open All Night celebrity news.

Obama's Iowa effort has aggressively courted "Generation Y" -- including high schoolers, since people can caucus at the tender age of 17. It's the only campaign to launch an official Facebook application to organize and gather data about potential caucus goers. And today marked the launch of a "Facebook Primary," a joint project with MoveOn.org, the Hip Hop Caucus and the League of Young Voters:

It's based around a Facebook application, where people can vote for and promote their favorite candidate, and identify their top issues as well. You can see not only who's winning nationally on Facebook, but also who's winning in each Facebook "network". In other words, it automatically starts a primary election race in each city, school, workplace, etc.

Part of the idea is that users will get a kick out of competing in their own networks, or discover that some long lost friend is backing the same candidate, which they'd never know otherwise.[Update: The primary application on Facebook is not sponsored by the company.] Offline, a local "Rock The Caucus" program has also been pushing youth turnout, as The Nation's Cora Currier explained.

Will these "Field 2.0" efforts actually turn out more new voters? I'll try to answer that question the magazine's next issue...