Sometimes they'll merge the two. What shows up on the FP is hit or miss. One might even say it's stochastic.

I wonder if someone's looked into the optimal time of day and day of the week to post for maximum traction.

If I had to guess it would be monday morning pacific time when people would rather be doing anything than working.

Surely there's already stats on this or even a whole paper :P Could pull all dupe posts over time and see which ones are more popular etc.