Eggcorn Forum

The two sound very similar and the two phrases seem to be semantically linked in the sense of something being kept for future gain, except “prosperity” usually connotes fiscal gain while the original “posterity” usually refers to an object having personal significance (regardless of monetary value). One could prosper from something that one originally keeps for historic or sentimental value, and that may be from where the confusion between the more common word “prosperity” and the less common “posterity” results.

Some examples I found via Google (phrase in bold):

http://www.thewritenetwork.com/why-you- … ur-writing

Do you look back in anger or mild embarrassment when you think about your past scribblings? Are you a serial shredder or do you keep all your old writing for prosperity?

http://threetreesdontmakeaforest.org/blog/?p=19

Well we would if it was printed on virgin paper/tin and foil blocked/covered in PVC. But actually we love getting creative and clever cards which we keep for prosperity in our ‘nice /clever stuff from other people’ drawer.

http://www.fender.com/community/forums/ … 58083b0ce5

Well take the plastic off, but cut out the stickers you want to keep for prosperity and put them in your case or a drawer somewhere.

The eggcorn seems fairly uncommon (3,140 hits for “keep for prosperity” vs. 37,800 for “keep for posterity”, and 3,400 hits for the variation “kept for prosperity” vs. 88,800 for “kept for posterity”), but I thought the semantic confusion was interesting. Since most of the sites in my cursory search for the eggcorn looked to be from the US, I wonder if the eggcorn itself might also originate from the US.