For every block we create we earn roughly .80 Steem Power. But in order to produce a substantial amount of blocks, we need a substantial amount of votes. This is why witnesses campaign to get votes for their witness. And that's the difference between BTC mining and Steem witnessing. Instead of POW (proof of work) we use Delegated Proof of Stake (DPoS). Not only do we need the equipment to process blocks, but also the support from the community.
So there's a good chance I'll never make break even on my server expenditures, but then again, I could move up the ranks pretty fast if people feel they would like me to be witness. That's why I'm very thankful for your vote. :)