Steempower is the influence token of the site. You can convert liquid steem into steempower in a process called "powering up". When you power up steem, your upvote gains value. Having steempower allows you to get curation rewards as well. The more power, the more rewards.
Powering down takes 13 weeks. So, for easy math, lets say that you have 130 SP. If you power it all down, you will get 10 steem every week for 13 weeks until the whole 130 SP is powered down.
Powering up is what allows you to earn on steem, and allows you to reward others as well!
When steem is cheap, that is a good time to get a bit more influence on the site. Whenever Steem is under a dollar, in my opinion, that is a great time to get a bit more steem and power it up.
More tips for dummies tomorrow!
@thewitness, I gave you a vote!
If you follow me, I will also follow you in return!