sledbenik

1. follower; adherent
   On je sledbenik Gandijevih ideja. — He is a follower of Gandhi's ideas.
   Ta sekta ima mnogo sledbenika. — That sect has many followers.
2. successor
   Smatraju ga sledbenikom velikog slikara. — He is considered the successor of the great painter.

For social media followers, «pratilac» is usually used.