If your LinkedIn page isn't filled out, or has a blank face, or is filled with typos, you have saved the employer a lot of time, they can eliminate you quickly. If you don't have a LinkedIn page, then that also tells a potential employer that you really haven't paid much attention to the modern world for a long time.
But if you do have a LinkedIn page, with a current photo, and well-written descriptions of what you do, no matter how humble you may imagine your skills and experience to be, it says a lot about you. And here is the really weird part, which ties into human nature, a busy person may not ever even click on the link of your LinkedIn page, they will just be glad that you have one.
By the way, and I digress a bit here, don't ever, ever tell someone to *go look for something* on the web. Take the time to find the page, copy the link, and paste it into the communication. If you don't do that, you are advertising very clearly that you are lazy and sloppy. OK, end of rant about links!
By the way, here is my LinkedIn page. If you see any typos or anything, PLEASE let me know!
Oh yeah, and if you're a real hot shot, send a link to your Google+ profile. That's the big leagues nowadays. But do start with Linked in.
As my client +JOEL WELDON says, *it's the little things that get ya!* Pay attention to detail, you would be surprised how many people don't. And get that job! You deserve it!