There were (I think) a series of books in the 80’s/90’s about a group of teens (possibly in Australia) who found some technology and set up groups of other teens around the world and would communicate with them. Possibly to solve crimes but not 100% sure. Think it was also a tv series but not sure. Vague I know but any ideas welcome! Suggestion from Lost Classics reader beholdthething: either the Internet Detectives series by Michael Coleman or Cyber.kdz series by Bruce Balan.
Second suggestion from LOst Classics Reader Rori: the novelization of The Tomorrow People.
Lost Classics of Teen Lit: Name That Book! 