Hypothesis:
each of Q's posts is a "stringer" in some way
Sentences ending in a . are letters.
Sentences ending in a ? are meant to be taken in sequence to form a number; i.e., if five questions are asked in a row, then that character in the stringer is "5".
Special characters within different sentences - possible additional characters in the string.
Strings are meant to be formed from same-day posts (possibly decrypted in some way?) and used to hint at future action without revealing everything/giving info to bad actors.
I'm just spitballing here, so enjoy the cube of salt that goes with this.