If you vote often the power with which you have to influence content is diminished.
In steems whitepaper they have rate limited voting built into their algorithm. Basically someone who upvotes many things in a short period of time has each sequential vote have less power to influence content than someone who votes occasionally every so often. (This helps keep bots that would automatically like everything at bay).
The charts above shows how a user’s voting power decreases every time they vote and then regenerates as time passes without voting. These charts use nominal time unit and could be made to scale to any targeted voting rate. Note that voting power rapidly drops off during periods of continuous voting, and then slowly recovers. (From Steem Whitepaper)
So basically steemit has created a system where it wants you to upvote comments and posts that actually provide something. So upvote accordingly :).
To the best of my knowledge there is no limit on the amount of posts you can make, just the voting power is limited by frequent voting.
I'm very new to the community, but this was something I was curious about. Hope it clears things up to any of those clicking everything in hopes of making money only to realize they would have better spent their time finding the best and most helpful content.