This is exactly the issue. As sucky as LinkedIn is, it actually did result in better results for me than average HR department at a given company. That should not be the case, but so very often it is.. therefore, LinkedIn remains one of the viable options.

I am relatively lucky, because I am now old enough to have friends, colleagues and some reputation so I do not need it ( amusingly, my profile was flagged for something recently and I have not looked back ), but I remember when I did and recruiters were the least painful way to get my foot in the doors