Do I earn in posting even if i'm not in campaign?
No, it's like just engaging with this platform. Like using social media, just participating but not earning anything. If you're posting and you are not under a signature campaign, who will reward you? the site?

You are a Jr. Member already and is very much allowed to participate in Bounty campaigns especially in signature campaign. Do sign up for great campaigns. Look for a forum topic which will give you an idea about Bounty campaigns projects, and ICOs and how will you identify if it has a great potential or not. Only then upon participating and eventually completing the entire campaign, you'll get your reward money. If you're still lacking with the idea of Bounty campaigns, feel free to use Bitcointalk.org search tab.
