It was a brief but controversial trial program last year that saw the likes of Unabomber Ted Kaczynski, Romanian dictator Nicolae Ceaucescu, and Monica Lewinsky's stained dress become official U.S. postage. Now, online postage company Stamps.com (NASDAQ:STMP) is back at it again, reinstituting the custom stamp program with the Postal Service's stamp of approval.

But there are restrictions.

Since so many people thought it too imprudent to have controversial photos as legal postage, Stamps.com is forbidding customers from submitting pictures of politicians (both U.S. and world leaders), celebrities, or criminals, as well as anything that smacks of being "newsworthy," offensive, obscene, unlawful, "or otherwise objectionable." This is perhaps not as draconian as the prior ban on any adult or teenager photos, which left little else to put on a stamp other than a still life setting or Uncle Fred's favorite recliner.

To ensure that people won't become upset by seeing photos of a pregnant Britney Spears gracing an envelope (hmmm, maybe these restrictions aren't so bad after all), and to ensure the Post Office doesn't cancel the program again, all submissions will have to go through screeners who are supposedly proficient in picking out historical figures from old photographs. Yeah, OK. Each stamp will go through two screeners, and the company has supposedly amassed a library of tens of thousands of images that are considered no-nos. The Post Office is satisfied with the company's efforts to stamp out controversy but says it has no intention of getting involved in censorship.

Official stamps are recognized by sophisticated Postal Service sorting machines, which scan each stamp for a special watermark to prevent counterfeiting. Stamps.com's PhotoStamps have such watermarks, as well as secondary marks that serve as bar codes to also foil counterfeiters. Other companies are being solicited to produce similar stamps. The program is expected to begin again this month.

The leading provider of online postage has reported good results even without the PhotoStamps program. For the first quarter, Stamps.com notched a 56% jump in revenue to $11.8 million and an increase in gross margins to 73%, up from 61% last year. It was the company's 11th straight quarter of increasing revenues and its third straight quarter of profitability. That compares favorably with the mail-related products and services company Pitney Bowes (NYSE:PBI) which reported a $15 million increase in revenues to $1.32 billion and a $20 million increase in earnings, only a small portion of which is related to online postage. According to Stamps.com, it owns 85% of the online-postage market.

Investors became unglued at the revival of the PhotoStamps program and bid up the company's shares some 18% on the news. Assuming customers can contain themselves from trying to slip photos of mass murderers, pop idols, and other offensive subjects through the screening process -- think of just a nice fruit bowl or pictures of your cat Fluffy -- the PhotoStamp program should have the naysayers licked.

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Fool contributor Rich Duprey thinks about going "postal" when sitting in traffic. He does not own any of the stocks mentioned in the article.