RE: A new member saying Hello

Others might chime in with more details but I can hit some of the highlights.

Hive Power = Staked Hive

Your resource credits (RC) are based on how much hive power you have. To perform any operation on the block chain (including posting, voting, etc.) requires resource credits. However, these recharge over time so you don't actually consume Hive Power or anything. You just need to make sure you have enough hive power that you don't run out of RC in the course of your typical activates in 24 hours. It doesn't take much. 100 or so is probably sufficient for most people.

Advantages of powering up your hive (i.e. converting to Hive Power): The more hive power you have, the more your vote is worth and the more you earn from curation (upvoting posts), Hive Power also earns interest (currently about 3%) whereas liquid hive does not.

Disadvantages: Converting back to liquid hive takes four weeks (e.g. if you choose to power down 100 hive you will get 25 per week).

There is also HBD (Hive Backed Dollar). This is an algorithmic stable coin worth about $1 U.S. If you decide to keep these (50% of your earnings will be HBD) it is best to put them into savings as it will earn you 15% interest currently. It also takes time to get HBD back out of savings but only 3 days. You can purchase hive with them on the internal market or convert them to Hive if you prefer.

The top 20 witnesses (I think it's the top 20) make the governance decisions for hive (setting interest rates, accepting hard forks, and of course generating/witnessing blocks, etc.). Witness placing it determined by the votes they get. Not all vote are equal though, again, the more hive power you have, the more your vote is worth. You can vote for up to 30 witnesses.

Regarding curation (upvoting posts), you get the equivalent of 20 full powered votes per day. You'll notice when you vote your voting power goes down meaning the next one is worth a little less. However, this recharges over time. If you make 20 100% votes then you will be back to 100% voting power in 24 hours.. If you have enough hive power, you can adjust the voting strength of each vote. In other words, you can vote, for example, at 20% instead of 100% making the vote and curation earnings worth less but allowing you to distribute more votes. I don't recall how much hive power you need to adjust voting strength.

Delegating is basically a way to lend hive power (or resource credits). You can delegate to anyone and undelegate at any time (but again, there is a timing element. It takes a certain amount of time to undelegate). You'll see certain projects on hive that will basically pay you for your delegation in various ways (hive, HBD, 2nd layer tokens). It's a way to earn instead of or in addition to curation. Just keep in mind that your vote value/curation earnings are reduced based on the amount of hive power you delegate. If you have 1000 HP and delegate 500 then your vote value/curation earnings will be the same as if you only had 500 HP. It would go back to normal when your HP was completely undelegated.