If you are constantly looking for work online then chances are you are probably signing up for sites, entering your email address, and other information.
I receive a lot of emails now since I joined quite a bit of different sites to make money. From emails telling me that my articles were approved, survey invitations, news and promotions and occasional junk emails.... that is a lot of emails to go through in one day.
I have learned to check it more often.
I've also noticed that I have received a few "fishy" emails.
Be skeptical of any emails that are sent from people or sites you don't know.
Be skeptical of people saying they want to hire you in an email, especially from unknown sources.
Be skeptical of emails that actually look legit but are not. You would be surprised how scams can look so legit. Especially when they try and use the same names or other legit information.