I have received lots of queries regarding social media vetting. Even I was in the similar situations before Visa. Here are my findings:
1) Your Visa hardly gets denied due to your activities on social media accounts.
2) Being chronically online with regular posts, owning large accounts don’t make you susceptible. I have large accounts at many places. ( Insta: 11k+ followers, fb 5k+ with multiple pages, YouTube subscribers and vids etc)
3) The VO looks for pointers for you being critical to US or association with any banned outfits or mismatches in your linkedin profile and DS160. Essentially, they look if you’re a genuine student.
4) Your Visa gets denied due to school reputation( is it a diploma mill?), lack of fundings and scholarship, and not showing enough pointers for your intent to return to your home country.
5) Your Visa may get denied if you memorize your answers and offer too much details.
6) Be natural and focus on your strengths.