you can only join chess canada if you are Canadian! lol
Top 3 groups that you should join on chess.com

SebLeb friends : http://www.chess.com/groups/home/sebleb-friends
Chess Canada : http://www.chess.com/groups/home/chess-canada
Chess is wonderful : http://www.chess.com/groups/home/chess-is-wonderful

you can only join chess canada if you are Canadian! lol
Well it seems that there is immigrants that are in the group ! lol.

Well if you're a strong player I'd imagine either Legion or the Power of Chess would be on your list of groups to join. Thematic Matches and Tournaments to practice various openings, or other random opening groups. And lastly one of the GM groups if youre a fan of a certain GM and want to see their games or talk to them if they are a member of chess.com. (also for people loving endgames there are groups for that, are for recommendations on chess books there are groups for that).

Reasons why you should join :
SebLeb friends : This is a group that is getting bigger and bigger all the time. We have very good vote chess games that are currently happening right now. We have a FM that is in this group. We have some amazing people that are in this group that really helped me keeping my forums strong and popular as much as possible without me even asking them. I really appretiate what my friends do for me and what the fans do for me. ( wich I have talked to and suprisingly, yes they said they were huge fans. ) So please join this group of awesome people. See you there !
Chess Canada : So, we Canadians do no harm to anybody. See for yourself ! This is a great group that nobody hates nobody. We have amazing team chess matches and we are renound for it. They are wonderful and interesting games. See you there !
Chess is wonderful : Great staff. They are persistant to keep the group popular. We have a WGM that is in the group and active. The forums are active. There is great people there. They know how to keep the group going.

Well if you're a strong player I'd imagine either Legion or the Power of Chess would be on your list of groups to join. Thematic Matches and Tournaments to practice various openings, or other random opening groups. And lastly one of the GM groups if youre a fan of a certain GM and want to see their games or talk to them if they are a member of chess.com. (also for people loving endgames there are groups for that, are for recommendations on chess books there are groups for that).
But you need a group that knows that you are there ! They wont realise you there. You will not feel part of the group !

I would say that theone group you should join on chess.com is The Dan Heisman Learning Centre.
Anyone disagreeing with me can join us for a week or a month. And i ll bet that you will like it. Most opening themed grouos are inactive i have joined some 10-15 of them. Is there any opening group that is active?
Go DHLC (no offence to others)
Oh gosh, DHLC gives way to much messages. Like at least 10 a day.

I would say that theone group you should join on chess.com is The Dan Heisman Learning Centre.
Anyone disagreeing with me can join us for a week or a month. And i ll bet that you will like it. Most opening themed grouos are inactive i have joined some 10-15 of them. Is there any opening group that is active?
Go DHLC (no offence to others)
no offence but it doesn't actually give that much advice exept the advice that Dan give. The WWLC actually has lots of advice on many topics and encourages people to post and will get reconnized when they put usefull advice.

Sorry ! Never been there lol
you should join, you were voted troll of the month when it still existed.
1. SebLeb friends
2. Chess Canada
3. Chess is wonderful