It allows you to stay in contact with old employers and coworkers you don’t necessarily want on your facebook page.
You can add in all the info that would make your resume look too long and add your LinkedIn profile to your resume instead.
You can see who your contacts are linked to and ask for an introduction.
Recruiters do sometimes approach you regarding suitable positions.
Yes, LinkedIn has its benefits, but I’d advise you not to make it the key focus of your job search. Ideally it should only take you an hour or so to set up and aside from checking in once in a while and making updates as required, it should be able to maintain itself. In the meantime you should be focusing your job search on activities that gain you traction like writing a nice old fashioned letter to the management of the organisation you want to work letting them know you want to work there and including a copy of your resume. The thing that I’ve noticed is that with ev
erybody jumping on new technology like www.seek.com and www.linkedin.com, a good old fashioned letter snail mailed to the employer seems to jump out at them and get better results so make sure you include this in your job search action plan.