What does 'by' mean in the context?
Ji Won Kim, a doctoral student at the university’s S.I. Newhouse School of Public Communications, worked on the study. She said because social media can be superficial, it is a good place for people to “work towards satisfying their own vanity.”

By superficial, she means social media is mostly used by people to share unimportant information about their lives -- not deeply personal issues.

Does 'by' mean 'with'?

Question

What does 'by' mean in the context?
Ji Won Kim, a doctoral student at the university’s S.I. Newhouse School of Public Communications, worked on the study. She said because social media can be superficial, it is a good place for people to “work towards satisfying their own vanity.”

By superficial, she means social media is mostly used by people to share unimportant information about their lives -- not deeply personal issues.

Does 'by' mean 'with'?

Answer

Yes, if you're a Portuguese native speaker

Answer

"By superficial, she means..." means "When she uses the word 'superficial,' she means..."

The second sentence explains what exactly Kim is trying to say when she uses the word "superficial."