A case against open networking
When I started working as a sourcer, it quickly became apparent that what was expected and seen as a proof of success was a large network, mainly measured by the number of connections on LinkedIn. Open networking is aimed at getting you just that by accepting all of the random requests you encourage others to send you.
At the time it made sense as it allowed you to review more profiles on LinkedIn without having to find your 3rd level connections through an external search. But ever since the commercial search limit has been introduced, a more targeted approach to networking seems to have more advantages.