LinkedIn has ‘networking’ at its heart. There’s little ‘social’ here, just people you may have worked with or had some connection with. This makes it a very useful resource for sharing ideas, developments and promoting your talents or, possibly, searching for others with talents you may need for a project or role.
The site design has improved immensely recently and ads are mercifully pretty much absent.
There are some interesting groups that you or students may wish to join and, of course, it is a good resource both for illustrating carers as well as potential opportunities.