I have twenty years in IT doing contracting and LinkedIn has been a great source of work. However the signal to noise ratio is getting worse and I no longer read the posts due to all the low quality content. For a recruiter it's great to be able to mass mail your search results when trying to fill a position. It's no different than the other job search sites in that a majority of the contacts I get from recruiters are for the wrong type of work, wrong technology or pay too low. I don't bother trying to explain that I did .Net many years ago but don't do that now because most recruiters have no idea of what .Net or Angular or a SIEM is anyway.