As you write posts you earn some Steem Power. Also if you buy Steem and power it up you get Steem Power. The more Steem Poweryou have the better your own personal upvote is worth. The higher this upvote is worth the better. Like society people tend to group up based on wealth. The more SP you get the more curation rewards you get the faster you grow.!
I figured out a way to lease it using @minnowbooster. Also I built a neat delegation tool that allows anyone to delegate to anyone https://SteemThat.com