From the wiki article:

The value of gifts you receive is calculated based on the cred*, charisma, luck and number of unique forums pwned that day. The exact formula is only known to ET so far.

Luck, charisma and cred* govern the value of the items you recieve, the number of unique forums pwned that day governs the amount of items you recieve.

(*specifically the change in cred earned over the previous day)

But since the fans system is relatively new, that might be out of date. Seems like fans ought to affect deliveries since they’re the nominal explanation for the gifts you receive. Fans earned could replace cred earned as the measure of your days pwnage, but it’s more directly a replacement for speedruns in working out how many lemon scoops to award.

Whether the best thing is to maximise the sum or the product of your Luck and Charisma… again, still needs to be spaded out. If fans is a factor it could be hard to separate it out though.

Edited after I saw Banhammer’s posts: Like I thought, fans is the replacement for speedruns, so it’s just the luck/charisma balance that needs to be worked out.