social media

Red flags -
- pictures you wouldn't want your parents to see (of course pictures of this type shouldn't be on social media anyhow)
- pictures with obvious alcohol in cups/bottles, etc. (same as above, why post such in the first place).
- excessive swearing (simply no need for it on social media)
- a lot of solo selfies (because that's just weird and egotistical)

Sororities are wanting new members who will represent the chapter well on campus and in the community. As far as current members adding/following you on social media, it's probably a good thing but don't read too much into it.