Hi Reza.

Okay, so up votes determine how much content producers are rewarded for their work. Not all votes are equal though - the value of your up vote is determined by how much Steem Power you have. Since the latest hard fork, up votes from 'minnows' (you and me) are worth more, but we can't vote as often either.

If you vote too much, your voting power will decline and your votes become worthless. Your voting power recharges by 20% per 24 hours, so the idea is to not drain your voting power below 80%. Since the hard fork, that equates to about 10 up votes (maybe 11) per day. As such, you shouldn't throw your up votes around willy nilly, but only give them out when you come across GREAT ORIGINAL CONTENT.

I just checked your voting power and you're down to 32.36 percent - this means you need to have a break from up voting for a few days. If you don't place any more up votes, your power will be back to normal in a little over 3 days. For future reference you can check your voting power (or anyone elses) here.

Hope that's adequate and let me know if you have any more questions.

Cheers :)