They post job listings on Upwork for contract recruiters. They schedule you for an "interview" and during the interview state that they would like you to give them feedback on their platform. I was open to providing them with feedback because I have assisted software companies in the past with this. You have a second meeting to provide your feedback and the guy you speak with, who I learned is actually their sales guy, takes your constructive feedback and then gets offended by it. Then you start getting spammed by them to purchase their software. Come to find out they really are just using job boards to get free work, gather your data, and sell you their product. Do not apply to their job openings. It'll just be a huge waste of your time and now they have your data as well.