Once a year I get an automated email from linkedin indicating that some of my contacts have changed jobs and to click here blah blah blah... I probably deleted more linkedin emails than from any other source. Then last year, I clicked through and found a nifty resource, Year in Review. Of course, LinkedIn keeps track of every change to a person's profile and broadcasts it through email, status updates and the like. Year in Review (YIR) culls through all of the changes and reports on everyone of your contacts who has changed jobs over the past year, in chronological order. Click on the link, sign in and you will see the faces of everyone who changed jobs last year (and prior years).
Business development nexis? Right click on a face and open it up in another browser tab. Do that for the whole row. Click through your tabs and ask yourself if that person is a potential client, referral source or valued friend. If so, spend some time reconnecting by email or phone. Congratulate them on the new gig. Ask them how it is going? Learn about their new firm or company. Look for opportunities to help them or expand their network. Set up a lunch date. Don't pitch, just show interest and offer your help and network.
Done with that row? Go to the next. At some point (maybe 6 or 12 months or more) their job is no longer "new" and you might want to change your message.
Keeping in contact with your network is important. Use linkedin to identify a reason to email or call and do it.