I asked lots of questions to the founder of the company I was at. He was very nice in always answering me and helping me understand what's good / bad. I try to pass it on but I'm not sure how to proactively get the knowledge other than reading something like "All about VC fundraising" (fake post, I'm sure it exists) and hoping it's there.
Participating preferred = investor invests 50M on 1x participating preferred and company sells for 100M. The investor makes 50M + their % share of the company. Common stock makes % share of 50M.
They participate in the % sales ON TOP OF their preferred stocks liquidation preference (money in = money out before common stock value is considered)
Now here's where it gets nasty. 2x participating preferred = investor invests 50M and company sells for 100M. Investor makes 100M and common stock makes $0. Or if the company sold for 150M, investor makes 100M and participates in the % stock value from 50M.
It's a bit confusing, but the short is participating preferred is the absolute worst terms for common stock holders (founders included.)