I would strongly caution against such threads, and the type of social media exam question discussion which at least one parent has alluded to. This cautionary statement is based on College Board's published exam day policies, and exam security (see excerpts below):
Remember, whether it is during breaks or after the exam, you must not communicate anything to anyone, including your classmates and your teachers, about the multiple choice questions that appeared on your AP Exam.
Discussing Exam Questions
Do not email, text, post, or in any other way circulate AP Exam information through any kind of social media, or your AP Exam score may be canceled and you could also be banned from taking future AP Exams.

Also, you may talk about the free-response questions from the regularly scheduled exam two days after the exam and only if your particular free-response questions have been posted to the College Board website.
Originally Posted by College Board - Exam Security
Discussing Exam Questions
The College Board will automatically cancel your exam score if you are discovered disclosing:

multiple-choice questions;
free-response questions from an alternate exam;
free-response questions from a regularly scheduled exam within two days of its administration; or
free-response questions that are not released on the College Board website two days after the regularly scheduled exam administration.

This means that something you may not have intended as a violation, like casually talking about a multiple-choice question with your friends...

You can only discuss free-response questions from a regularly scheduled exam after two days have passed, and if that particular free-response question was released on the College Board website.
The free-response questions which have been released by College Board are found on the AP subject's Exam Practice page, for example AP HUG Exam Practice page. Although hovering over the exam questions for any given year reveals the link, it is anticipated that individuals will sign in to their College Board accounts to view the material.