While a large LinkedIn network is beneficial, the real value comes from knowing what's going on within that network, says Kelly Lux, the online communication and relationship manager at the School of Information Studies at Syracuse University in New York. According to Lux, one of the best tools available for LinkedIn, Job Change Notifier, keeps track of your network and alerts you whenever someone gets a promotion or moves to a new company.
"There are two scenarios that Job Change Notifier can help with," Lux says. "First, you've had your eye on a job that a connection is now vacating. Second, one of your connections is now employed at a target company. Sending a note of congratulations in either of these instances, along with a mention of your interest in either the new or old company, may help you make the connections you need at just the right time."
In either case, Lux says it's important to move quickly because job changes present only a temporary window of opportunity. But also be tactful because you don't know the circumstances of the job change. If you don't hear back, Lux says to follow up in a week, since your connection may have been deluged with notes.