I have been beating you over the head with the notion of actively building and expanding your network of contacts and referrals - not only for job search activities, but also for ongoing career management.
Beyond the occasional "join my network" emails through LinkedIn and status updates through Facebook - assuming that you actually use those two social networks), do you know where your network is?
If you have been happily employed for many years, that is no excuse to neglect your network and take your personal and professional contacts for granted.
So how do you stay in touch with people throughout the year without being intrusive?
-- Make a list of birthdays and anniversaries so that you can at least send a card in the mail or an e-card. If you are close to the person, acknowledging their children's birthdays as well is not a bad idea.
-- Make an effort to send out an email at least once a year just to check in - how are you, what's new, still at the same job, etc
-- Make sure to inform your contacts everytime you get a promotion, new job, interesting or high-profile project just to keep them abreast of your career progression. Remember to be receptive and congratulatory when the same information is sent to you
-- Make plans to meet in person with your top tier contacts every quarter if you live in the same city, state or regional area
--Make yourself available for recommendations or referrals when anyone of your contacts is seeking to make career moves
-- Make good use of Linked, Facebook, and Twitter to give everyone brief, but informational updates on your weekly activities
Over at the Wall Street Journal, read an interesting article on Ways Job Seekers Can Find Old Contacts
