The first thing I've learned from on line job: Be aware of scam

This is the result I've come up with. There are just tons of on line jobs, and of course, many people are talking and writing about it.. including me. I know there are more advance and professional reviews on websites, but what I want to do here, is just to share my experience as a beginner in on line jobs because I know that we might share things in here as well.

The first thing that I have learned is that as well as there are so many legitimate on line jobs, but there are also ilegitimate ones, and they are scams. They are probably scam if:
1. It requires you to send them money to sign up to their account
2.The graphic format of the website looks very amateur compare to legal websites who have real on line jobs.
3.They don't tell you the location of their head quarter
4.If earning money from their version of on line job is too easy.
5. They don't put many features and menu in their sites, so it is more to directing you to send them money

These are the things that I have learned, and I also read many of people's experiences from scams. Of course, what I wrote here is not an opinion of an expert. But there's nothing wrong by being aware of scam. So be aware and becareful.