Writing to offer a piece of information or a connection is a great way to demonstrate that you're looking out for the other person. Humans have a tendency to want to reciprocate, so the more you show you're looking out for someone, the more likely that person will begin to keep you in mind as well.
A cup is useful only when it is empty; and a mind that is filled with beliefs, with dogmas, with assertions, with quotations is really an uncreative mind.