So from what I understand the 50-50 slit is about how much goes into the two pools in your wallet. Either Steem power or Steem dollars when someone up votes your post.
Nether of which can leave steemit. If you want to cash out you need to transfer it into a steem (the currency worth money)
Steem power
Is how much influence you have, it represents how much you can give to others and by that I mean it is a free hug type situation. You don't loose power by giving a hug.
Steem dollars
How much money (steems) you would have if you cashed out but you get interest over time so leave it in the steemit 'bank'.
See Link for the complicated answer
Also you only get so many free hugs (upvotes) a day, I think it is 20 but I can't remember where I saw that, before the value of your up-votes becomes affected. If you give out hundreds of free hugs (upvotes) they aren't worth much anymore
If you have sufficent STEEM Power (I believe it's 500 SP), you can give upvotes with a percent you'd like. This way, when not voting at 100%, you can vote on even more posts 🙂