A few months ago Xomba decided to stop their referral program. A referral program is a way that you can earn money by telling your friends about the site. When they sign up, you get a percentage of their earnings. This is a way that the site can say thank you to you for telling your friends.
One day Xomba had their referral program in place and the next day they didn't. I fully expected they would continue paying out for past referrals, just stop future ones. But that is not what they did, they stopped paying everyone for all referrals. Some people had put effort into sending people to Xomba's site and had many people join under their referral code, but they lost that stream of income overnight.
I thought this was very unfair, but the moral of the story is that it is Xomba's site and they make the rules. That's why it's a good idea to write in many places and not just one. At any time the sites you write on can change the rules or even disappear. If you write 1,000 articles on one site and suddenly it's not there any more, then you have lost all your income. If you wrote 500 articles on one site and 500 on another and one site disappears then you have only lost half of your income.
The world is changing and the online writing world more so. Just be ready for the changes when they happen.