That is actually a very good point and one that I currently cannot answer. It could easily be a mix of the incentives and people's preference for whole numbers (just like it felt MUCH more impressive when BTC hit 10K than 9.99K or even 12K). I guess it would be interesting to see the logs of any similar apps that do not reward users directly (ideally both one that requires people to post daily and one the does not).

An interesting experiment could be to set the actifit rewards at for instance 5128, 6128, 7128... 10128 and see if that would change people's behaviors. That is sadly outside of my power, though :)

Thanks for you post and happy actifing to you too.

(To others reading this, I am seeing your interesting comments too, but my Resource Credits/Mana is too low to answer right now :( I even had to power up to make this comment. I will get to you as soon as possible.)