Anyone wants to work with those who has excellent capability, professional skills and passionate emotions, I believe. To recruit such people, they need to offer good working conditions (salaries, benefit packages, place, office, colleagues etc.) to employees. But to almost any startup can't afford these stuffs.
Then, what should they offer to new employee candidates? While each startup company can provide varied conditions, one of the answers will be to have reasonable missions. When the missions are acceptable for the applicants, they will join to the company.
To state so is easy, but to establish such good missions is not so easy to us...