User Investment: Make Your Users do the Work
The Startup Grind Team

Nice article! Here are two additional sources of information you might find interesting: In his book Your Money Your Brain Jason Zweig talks about how investors a) anticipate a pattern after something has appeared twice in a row (e.g. if a stocks goes up twice people would believe that it will go up a third time as well). This goes, from my point of view, hand in hand with the principle you have mentioned about people coming back to use the product after they have invested into it.

Closely related to the studies you have mentioned about people committing to something after they have put effort into it, is the Ben Franklin effect which says that people are more likely to do like you after you have asked them for af avour.