Its ironic that that [[http://www.lifehack.org/|Lifehack]] is going around [[http://www.lifehack.org/articles/lifehack/advice-for-students-twenty-uses-for-a-post-it-note.html|telling students]] that some of the best uses of Post-its are to use them as bookmarks and to mark passages in books. Ironic because most libraries tend to have //very// strong views **against** Post-its usage. Here’s a sample:
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.
Although these notes seem harmless, the glue they use is not acid-free, and can harm the books. Also, pages can be torn easily when the notes are removed. If you need to bookmark certain pages, we ask that you use paper or thin cardboard bookmarks.
We frequently point out to readers that they should not stick adhesive notes into our books. The readers are usually surprised because they believe them to be harmless. Any brand of mildly-adhesive repositional-note presents us with problems. Firstly, the notes can get trapped when pages are turned and the text gets ripped along the shear line at the edge of the notelet. Secondly, the mild adhesive is strong enough to remove the nap from fine antique papers and lift the print off the page. Thirdly, the notes were not designed by Conservation staff thinking about books that will be kept for centuries. And our conservators are concerned that the residual glue and chemicals, deposited on the pages of books, will eventually discolour or chemically change the paper.
Maybe you want to revise your list Lifehack? Or atleast give a disclaimer?