They are a group that gives upvotes on posts for the newer members here. Its a way to help the new people earn some money and stay encouraged over time. Because they click on your link and upvote you, you earned a little more on your post (same thing with @resteemable.
They get donations from the bigger members that want to encourage the new members like yourself. I like them because they really do help boost the moral... A 1 penny bump in payment means a lot in terms of psychology as positive reinforcement. Especially to some of the poorer parts of the world (just now getting connected to everyone else), and it adds up and encourages them to keep improving.
So any time you post something original, should go to your own post and do what I did and type in @orignalworks and they will see your post and validate it. You can keep doing this as long as you are small and still learning, but once you get bigger you will want to let them use their funds for the other new people. The great thing about this platform is that new people are coming in every day and as the network gets bigger, it gets to be an even better place to be. So everyone wants to continue to teach and train the new people because it is in all of our interests to have a great strong and growing community.