After getting my first Nigeran Scam from a Unity Connect applicant I was thinking that this system has a lot of features that make it desirable for scammers. 1) Its trivial to apply for many jobs. 2) The way you create your profile pages makes it easy to create a professional seeming portfolio that is hard to differentiate from a real portfolio. 3) (The big one for me) The way the application process is set up it requires the job poster to see and review a portfolio and to take actions by 'accepting and connecting' to the applicant. 2&3 make it easier for the scammer to build trust when no such trust is deserved. Contrast this to a forum post where the first interaction is a hand crafted message. This requires the poster to reply to what you wrote and to tailor their approach to your specific requests. It makes it both harder for the scammers to reply and easier to pick the scammers at the first interaction (before any trust is built).