Rihanna knows exactly what her audience came for ... 'cause she's promoting Fenty hair products in her most recent post -- but, a whole bunch of people online are going ...

Rihanna wore a Joseph Davide cardigan, the clothing brand of the son of Joe Tacopina, A$AP Rocky's lawyer in his felony ...

And clearly wanted to show off her Halloween costume: Since Sunday, the singer has already uploaded 14 photos. She's clearly happy to be back, so why the long absence? In April, Rihanna posted ...