Jacqui Cheng summarizes the change in app rankings that rank-tracking services noticed a few days ago:
This week, however, several companies began observing changes to the ranking system that appear to weigh more heavily on factors other than the number of downloads.
Nobody seems to have figured out what the new algorithm is based on, but it seems to only have affected free apps so far, and it seems to favor new apps. The changes also don’t seem to be upsetting many (if any) “legitimate” developers.
If anyone has more information on this, I’d love to hear it.
(For whatever it’s worth: Instapaper’s rank hasn’t noticeably changed beyond normal minor fluctuations, but it’s a paid app that’s updated regularly.)