The New York Times celebrates the thirtieth anniversary of Post-It Notes, a great innovation of the late 1970s national malaise, perhaps because it introduced a bit of sunny yellow into the gloom of the stagflation-era workplace. It also illustrates how bold marketing in difficult times, and user ingenuity, can complement each other:

Notepads produced for internal use at 3M were a hit, but when they were tested in four markets in 1977, shoppers showed little interest. The next year the company descended upon Boise, Idaho, for what was known internally as the Boise Blitz. Free samples were widely distributed to offices, and so habit-forming was the product that more than 90 percent of Boiseans given samples said they would buy it.

When the brand was officially introduced in 1980, using just yellow pads, the company again circulated free samples liberally, including to chief executives of Fortune 500 companies and their secretaries.

Today, more than 1,000 Post-it products are sold in 150 countries, and the notes have permeated popular culture: A Post-it Note is what a boyfriend of Carrie Bradshaw uses to dump her in a 2003 episode of "Sex and the City," what the characters of Meredith Grey and Derek Shepherd use to write their wedding vows on in the season finale of "Grey's Anatomy" in 2009; and what the main characters in "Romy and Michele's High School Reunion" in 1997 claim to have invented since graduation.

Of course the success of Post-It owed a lot to the explosion of paper use that followed the introduction of the original Xerox copiers and their successors in the 1960s and early 1970s.

But there are hidden glitches in the Post-It and its clones. Read this warning from the University of California, San Diego library web site:

The verdict is in on Post-it Notes and similar adhesive markers! Though they are easy to use and may be removed from most paper surfaces, DON'T be tempted to use them in books. These seemingly harmless "markers" leave behind their adhesive, even when removed immediately. The adhesive hardens and leaves a film that becomes acidic. This results in eventual discoloration and brittleness of the paper. They were designed for short-term application to expendable documents and have no place being used on permanent records and books.

The National Archives and Records Administration (NARA) conducted research which determined that even when removed immediately, the adhesive residue remained. Even more dramatic effects result when used on newsprint (some of the ink is removed) or on brittle, fragile paper where removal may result in tearing the page. The NARA report concluded that these notes will cause increasing preservation problems when used with permanent records and should be avoided.

I haven't found the original report online, but there are further technical details here, and they've recently been confirmed by Chemical and Engineering News.The 3M FAQ page documents the notes' environmental friendliness, but according to the State of California recycling office:

Most paper collectors and paper mills still treat sticky notes as contaminants for high-grade paper. Furthermore, sticky notes are usually colored, which make them incompatible for recycling with white paper. Fluorescent-colored sticky notes are particularly problematic for the recycling of white paper. From a recycling perspective, it is best to simply avoid the use of sticky notes.

There's always a special risk in anything promoted as friendly, removable, reversible, safe, or otherwise benign, like safety pins. There's something to be said for products that look dangerous and permanent.