A few days ago LinkedIn launched a new iphone/ipad app (not on Android yet).
It reminds you to look at it for news about your connections: new jobs, job anniversary, birthdays (if anyone cares), etc. Keeps you and them top of mind.
I have to say I like it.
I have been using it to refresh old relationships, to stay in touch even if it is a few years since the last contact. They receiver of my well-wishes sees me again and can click into my profile to see what I have been doing. I can do the same to them.
Pinging on their radar screen is a good thing. Be creative and relevant in your wishes to the recipient. use every contact point well.