Two of my biggest use of LinkedIn right now:

1. Request for introductions. If there's anyone I want to get connected with, first place I go to is LinkedIn and see if he is friends with any of my friends. If a friend of mine knows him, I will ask my friend to send a personal intro.

2. Look for outside experts. Yesterday I was looking to connect with some iPhone game devs. I posted a discussion on 2 LinkedIn groups (GameDevs, and Social Game Devs), and I have received over 10 messages already.

It's a really powerful tool to create professional relationships.

Currently use it to find those hiring(seeking work now) and then find them on Facebook and message them there. Ppl use facebook everyday and supposedly recruiters and HR people are perusing social networks to help with their hiring decision, so I'm using such too to highlight myself from the crowd.

I use LinkedIn to gather info only, then find them on Facebook; they reply awesome, if not move onto the next one! I did subscribe once to LinkedIn and let them continue to charge my card. Though once i tried to cancel it i ended up in web consumer cancelation purgatory; they let u in but make insanely difficult to leave. All web services do this - ick. Have a dislike for LinkedIn and all that pull such crap!

I use it as a personal resume archive. LinkedIn has a feature where your work and school experience will download as a nice PDF, but I really just use it to archive my work. Then, when I'm preparing a resume, I cherry pick the most relevant parts and edit them to fit 1 page. I also provide it to employers so they can take a look at other work (and more importantly, recommendations) I have done (or received).

1. I have introduced people to each other, often via requests. Just recently I used it to pass on a request from a former colleague inviting another former colleague (at different companies) to speak at a conference.

2. I have got at least one job where the hiring manager found me on LinkedIn

3. It's my rolodex

There are other uses. It's not a high touch service, but definitely very useful.

I've used it to keep in touch with former co-workers after they've moved on or been layed-off. :-(

I started using it actually after a few of my friends have got jobs by using linkedin to contact former co-workers to see if their current workplace has anything available.

It's an easy way to find recommendations for professionals like accountants and attorneys. When someone is connected to or, better yet, recommended by someone you know, it's basically what you would get with a verbal recommendation while eliminating the hassle.

When I was looking for a job I'd find a potential job, then used LinkedIn to find who at that company I had some possible connection to. That was incredibly valuable.

I've never used it myself, but I have gotten job offers from LinkedIn