The most important question the Citizens United decision raises may be this: will corporations choose to exercise their new freedom, pouring money into campaign ads to support or oppose candidates? Rules advocates say money will pour in, but there may be some disincentives involved.

For one, the Supreme Court upheld disclosure and disclaimer requirements (over Justice Thomas's dissent).

Corporations that breach the $10,000 mark for producing or airing election season ads will have to file a report with the Federal Election Commission revealing the names and addresses of anyone who contributed $1,000 or more to the ad's preparation or distribution, according to ScotusBlog.

And "if a political ad is not authorized by a candidate or a political committee, the broadcast must say who is responsible for its content, plus the name and address of the group behind the ad," writes ScotusBlog's Lyle Denniston.

This could persuade corporations to keep their powder dry.

"Anytime you are confronted with disclosing something publicly, that becomes a decision point for a corporation," said Holland & Knight partner and political law group leader Chris DeLacy, noting that shareholder and public relations concerns could slow the influx of corporate dollars into the political ad world.

Another disincentive: tax considerations. "They won't be able to deduct [ad costs] as a business expense," DeLacy said.