We have all had people in our professional and personal lives who were at one time important contacts.... but over time we have drifted apart. It happens, there does not need to be a "falling out", but time goes by and we move in different directions.
(Granted, this happened more often before LinkedIn and Facebook showed up).
Think for a minute. Who was an important person in your life five yeas ago with whom you have not had any contact with in over a year? Think.... Think.... Think.....
There, someone came to mind.
Now, pick up the phone and call them. Or send them an email. Just say "Hello, I was thinking of you today" (you do not have to say "Some guy wrote something on his blog that triggered me to call you" - that might be creepy).
The call might not have any impact going forward. But maybe it will reconnect you with a person who matters to you.
It is much easier to rekindle a relationship than to build a new one.
Let me know if you have success (or failure) with this little exercise.
Have A Great Day.