I think there should be a category where you should read all of the signs in the game. I made a video speedrun of reading all the signs (https://www.youtube.com/watch?v=dMaLeSX6AMA). I have even some rules for this category:
Timing starts when you are clicking on the 1st level with the sign and ends once you ended reading last sign in the game. Try to read all signs, including easter eggs, like in Beauty and the Electric Tentacle and MOM`s Computer, MOM signs. You can read MOM signs/easter egg signs after you have read all regular signs. Speedhack, cuts or other sort of cheats are banned. Speedrun must be done on the save with fully completed game.
P.S. i forgot to read deliverance signs in this run

Maybe, some of the game speedrunners would like to make speedruns of popular World of Goo mods, like World of Goo 1/2, WoG:LiP, WoG:AtC. Maybe, adding WoG mods into the sub-games can help in growing the WoG speedrun community.