crown, diamond at the end of players name

what is the meaning of crown, diamond at the end of players name

It's their level of Premium Membership - a star mean Gold, a crown means Platinum, and a diamond means, well, Diamond.

See http://www.chess.com/membership

In other words it shows how stupid they are. I played a guy by accident who had a diamond next to his name- which means he's displaying how he's actually PAYING MONEY per month to be such a poor player.

That's one way of putting it.

I am a diamond member and I like it.  I searched the internet for a good chess site, and chess.com is the best I found.  Including the fact that they accept  non paying members to post in the forums, what allows people to troll them in such bad way and with negative criticisms. And still they allow new members to post, so they can get help.  Unfortunatelly, there are haters and bad trolls.  I am happy with chess.com and with my diamond account, period.  

Premium memberships have extra benefits like more vacation, auto-vacation (essential if you play lots of "daily" games), more Tactics Trainer, and more Chess Mentor.  I pay $29/year -- that's $2.42/month (less than the cost of a decent beer).  So I feel like I'm getting a great bargain.  If you really use Tactics Trainer much, then you might even go for the platinum or diamond membership.

I joined chess.com as a novice at 61 years of age and love every minute of it.  I have never had any training in chess, never had a tutor, etc but find that 10 games a day is really a good way to learn.  

Oh and it does say “please be kind” 

Chess.com likes to honor users who are of royal blood

I don’t get that one?