You can't use any words that appeared in the post immediately before yours. Talk about whatever, as long as it makes sense and continues the conversation. No double posts.
Example of good posts:
Post #1:
"Hello there, I have no idea what to talk about."
Post #2:
"Hi, that's too bad"
Post #3: "Yay, I get to use 'I' again since post 2 didn't use it."
Example of bad posts:
Post #1: "The, a, is, I, what, you, to, in, of, that. TROLOLOLOL"
Post #2: "..."
(contractions, like "can't", are counted as single word, but no purposely misspelled words like "u" to replace "you")
I'll start! This game shouldn't be too hard as long as people don't write very lengthy stories...