Each sub-reddit has its own set of rules, like being familiar with reddiquette, not spamming the group, not bullying or harassing people, and so on. The usual things you would expect from any group where people will be sharing information and replying to posts.However, some sub-reddits will have unique rules that you need to read and adhere to before you start participating, or you risk getting yourself banned.For example, some sub-reddits strictly forbid self-promotion.If you enter such a sub-reddit with the intention of posting about your products and services, you can expect to be kicked out quite quickly. Moderators are very active in their groups, and they don’t take kindly to having them hijacked.Other sub-reddits will want you to use a 9-1 approach. You need to post nine things that are not self-promotion (and are of value of course) before you can do one self-promotion post.It’s always worth taking a moment to read over the sub-reddit rules before joining, because if you don’t, and you break them, your posts will be downvoted (bad for karma) and you’ll be kicked out swiftly.