When attendees go to submit their question into the Social Q&A box, they'll see a character counter toward the top right, which changes color to yellow or red as they approach a suggested limit of 125 characters.
This is a soft limit. Users are not blocked from submitting really long questions.
However, you can configure your app so that there is a hard limit if desired.
To set this up, visit the Admin (settings) area of your app and look for the menu choice called Branding & Custom CSS.
Carefully copy and paste the following lines (starting with "<script>" and ending with "</script>") and paste them into the bottom box called Custom Head Section.
NOTES: You can set the Q&A length to whatever value you want. Depending on how you set the next line (true or false), you can decide whether users can still exceed that length. Using "true" for the QA_HARD_LIMIT, the user can't submit a question that exceeds the Max Length. If false, they can submit but they'll see a visual (red) counter value displayed.
var QA_MAX_LENGTH = 175;
var QA_HARD_LIMIT = true;