Quick overview on what a substantive message is,(check academic policy at the bottom of post) when you post your individual answer to a main Discussion Question (DQ) it simple needs to have a relation to the topic. So let say you are asked to write about the flue, then is obvious your answer needs to be related to that particular topic and not something like computer or anything else other than the topic.
Always remember to check the requirements of your facilitator on the word count. And when you participate in the DQ’s of other student make sure to give also a substantive answer to them, remember that saying the word “I agree” and submitting that as a respond does not count towards participation.
To verify your word count you can do it in two ways: the first one is to highlight your words on a Microsoft word document, and the second one is to check the word count on the university post window.
Check the examples bellow and a quick video. (Click on pictures for a larger view)
Always check the academic policies in case they change. (only students can access this link)