So you're thinking about joining a community board on Pinterest. The pins are great and it's a board theme you are totally into. You glance through it- not too many duplicates and you can already think of pins from your boards that would be terrific additions. You ask to join and are welcomed in. Now what?
Well, first off, go through the entire board if you haven't already. Try to notice what's already on there so you don't post duplicates. Nothing drags a board down quicker than seeing the same pins over and over again. Yes, even if you think your caption is better, resist repining.
Notice the tone of the pins. Is it a humor board? Are the pins primarily rated G or NC-17? Strictly one thing? If you ask to join a board you are telling the person that made that board that you wish to contribute within the parameters and topic they have set up. Stick with that. The board "owner" has the power to kick you off if you stray, but even if they choose not to, pinning off topic or inappropriate pins is rude to every other contributor and follower of that board. Don't do it.
Try to add pins that are linked to their creator or original site. Make sure the pin is not linked to a spam website. If necessary, change the caption to fit the pin. If you're not sure the pin fits the board, use the caption to state why it might. Pins should be of great quality- clear photos, proper spelling and punctuation, working links.
Part of the fun of community boards is that you're able to interact with each other. Leave (appropriate) comments. Like and repin freely. When someone comments on a pin you've added, it can start a great conversation when you reply back.
Lastly, feel free to leave if the board doesn't live up to your expectations. It only takes one discourteous pinner to change the atmosphere of a board. You don't have to stick around. You can start your own community board!
Hope this helps. There are so many social media outlets and the "rules" are often unspoken and vary greatly from site to site. Best rule of thumb though- treat others how you want to be treated!