Do I earn in posting even if i'm not in campaign?
yes you earn an activity but you doesn't earned any coin, in order for you to earn you must join a signature campaign because they will pay you for it because it is like advertising their service or platform in your signature . The higher your forum rank, the higher your payment will be.. So just continue posting.
No, you cannot earn unless if you are going to join in a bounty campaign program where you must be a jr. member,member,full member, sr.member, hero member and legendary. There are bounty campaign ads that requires high ranking members starting full member and upwards however, most of the bounty campaign ads I had joined accepts jr.member participant. You have to improve your ranking and you will soon earn.