Stickers started appearing after diary entries on the first of April 2014. They had numbers after them indicating how many of that type of sticker were attached to that entry. Diary entries would randomly get more stickers over time. The hero could convert ten stickers into a bonus. (They had to be the same type, but did not have to be from the same entry.) Gods had no control over this.
At first only three stickers existed, these were:
Ten arrows could be converted into a portable quest generator or used to boost quest progress.
Ten hearts could be used to gain health.
Ten stars could be converted into experience.
Later in the day, more stickers began to appear:
Ten flowers could be converted into a healing artifact. However, sometimes they gave nothing at all.
Queen's crowns (♕)
Ten crowns could be converted into gold.
Ten crosses could be converted into godpower.
Ten hands could clear the hero's diary.
Ten notes could be turned into a background music generator. (bold artifact)
Ten horses could be turned into a paper trojan horse (non-bold activatable artifact which teleports the hero to a random town for 50 gp)
Even later additions
Two more stickers were added even later:
Ten bishops could be usually converted into either a new piece of equipment (usually) or a bold item.
The hero apparently doesn't know what they do, but it seems that ten peace signs give a free accumulator charge.
12:24 I don't know what just happened, but I hope it was cool enough for Soul Supreme to like it.
As if to compensate for the usefulness of stickers, hints in dungeons were replaced with freezing (✵), cold (❄), mild (☁), warm (♨), hot (☀) and burning (✺). These indicated the distance to the treasure, the hotter the heroes were, the closer they were. This meant gods in dungeons did not know which direction to go to find the treasure.