Depends on your definition of "good"
How many points does one must have to be considered good player?

Depends on your definition of "good"
For me good player is which one developed his style of play, knows openings and is knolwedgable about game itself.

Depends on your definition of "good"
For me good player is which one developed his style of play, knows openings and is knolwedgable about game itself.
I peaked as a USCF A player, and didn't study openings deeply at all, and my style is blundering. And far as being "knowledgeable" about the game? By your own definition i suck at chess.

The players in America must be terrible if you can get to Class A if you blunder regularly.
Everyone blunders.

The players in America must be terrible if you can get to Class A if you blunder regularly.
or maybe ridicuously good.

Depends on your definition of "good"
+1
Chess ability (and "good" or not) is relative to your ability compared to your opponents. If you play chess against GMs regularly, then you may think you are not "good" even if you are better than the average; likewise being undefeated in your local area might create the illusion that you are "good", but maybe no one in your area is good at chess.
If you want to know how "good" you are relative to others on chess.com then check your "stats" page and view the percentile for a decent estimate to how you compare to other players. The chess.com average is around 1100 last I checked.

On Chess.com, I'd say 2000+, although 1900+ is solid. Much below that and you start contending with min/max players, making it difficult to compare similarly rated players.
Min/max players try to game the system to have a higher rating than they should be. It's somewhat common between about 1000 to 1600'ish crowd. I've seen games posted by 1600+ players that lacked some basic chess knowlege.
I have no idea how common, but's enough to effect the ratings system.

Recently I thought which rating person needs to have to be considered strong. Post your thoughts here!

Depends on your definition of "good"
+1
Chess ability (and "good" or not) is relative to your ability compared to your opponents. If you play chess against GMs regularly, then you may think you are not "good" even if you are better than the average; likewise being undefeated in your local area might create the illusion that you are "good", but maybe no one in your area is good at chess.
If you want to know how "good" you are relative to others on chess.com then check your "stats" page and view the percentile for a decent estimate to how you compare to other players. The chess.com average is around 1100 last I checked.
Recently I thought which rating person needs to have to be considered strong. Post your thoughts here!