The snowball analogy is a very good one.

The more you interact with other Steemians, the more your own efforts are recognized and rewarded by others.

And the longer those interactions are kept up, the more SP everyone accumulates. So it's a vicious circle but in a good way!! :-)

If there is one piece of advice I would give to newcomers it's this: comment, comment, comment on other posts and build up those relationships.