I'm not going to spend much time looking at LinkedIn, partly because I'm not going to sign up for it so the amount of digging I can do on it will be limited, and partly because I'm determined to spend more time on Twitter as so far I am still not loving it.
LinkedIn is probably the best known professional networking site, with over 200 million members worldwide. I searched for a few people I knew to be on there; those with unusual names I found without a problem, read their career history and clicked onto their personal/business webpage. Those with more common names I couldn't find; as an incentive to sign up you can only see the first 25 profiles for each name if you're not logged in, and although you can refine to search by UK only that still didn't help me find 1 person. You also need to sign in to be able to see the LinkedIn Connections that each person has.
I did a Google search looking for opinions of LinkedIn and it seems to be highly valued in some business areas, especially IT. I came across this recent Guardian article that reminded me the main purpose of sites like LinkedIn are to make money - interesting reading, including the range of opinions in the comments at the bottom; some saying LinkedIn is valuable to them, others slightly more negative.
If I was job hunting I would create a LinkedIn profile because it's free and there is always the chance it could be useful but for now I'm happy with face to face networking in the staff room with my current colleagues.
...I've had another quick look at LinkedIn, this time from the iPad. I'm still not signed in but this seems to show greater functionality than looking at it on a computer. I found the profile of someone I know and it had a clickable link to Skills and Expertise. I selected Fresh Produce and it took me to the page shown below. Interesting to see that Barack Obama is a fresh produce professional. Also interesting to see in the links on the left of the screen you can select 'Breathing' as a related skill...