People usually ask what does a “cofounder” title means in a startup.
There’s no legal definition that makes a person a ‘founder’. So when you see someone puts up the title ‘cofounder’ on his Linkedin or Angellist, it usually means he was one of the first few people involved in the initial days of the company.
I know an angel investor who agrees to invest in a company so long as the company also include him as a ‘cofounder’ of the company. Since the ‘cofounder’ title doesn’t have any legal implications, the company didn’t have any issue about such request. You can also have a ‘cofounder’ involved as a CEO in the company’s initial days but has since left and no longer attached in the company anymore.
I also know many entrepreneurs and founders get apprehensive about having people getting bestowed with the ‘founder’ title, especially when they weren’t around during the initial bootstrapped and grind period. So it perhaps also boils down to this concept of novelty, recognition, and prestige that comes with the ability to call yourself a startup ‘founder’.