Campus ministries, Tim Keller argues in Center Church, are important parts of a 'gospel ecosystem' in a city:

Specialized evangelistic ministries, raeching particular groups… of particular importance are effective campus and youth ministries. Many of the city church's future members and leaders are best found in the city's colleges schools…. Winning the youth of a city wins city natives who understand the culture well (p. 375)

He gives the exampls of Reformed University Fellowship, earlier in the book:

Another aspect of the spontaneity dynamic is the natural growth in leadership. This doesn't mean a church should not have fomal training programs. Rather, it means (1) that the vision of the movement… attracts people with leadership potential and (2) that the work of the movement naturally reveals emerging leaders through real-life experience and prepares them for the next level of leadership in the movement. An example is the Reformed University Fellowship, a campus ministry of the Presbyterian Church in America. RUF recruits recent college graduates to be campus interns, many of whom go on to become full-time campus staff. Working on college campuses trains workers to be evangelistic, to work with the emerging edge of culture, and to do ministry through fluid, nonformal processes. All of this makes campus ministeres who leave the RUF staff more comfortable planting new churches than taking positions in estabhlished ones. As a result, RUF has created a continual flow of dynamic, fruitful church planters and young laypeople… who are excellent core-group members for new congregations.

RUF is typical of dynamic movemenets in that it was not originally founded to produce church plantersl the powerful 'church planter formation' dynamic happened spontaneously, as the natural fruit of an excellent campus ministry. Most denominations, of course, create institutionalized agencies to recruit and train church planters, but organic leadership development pipelines such as RUF are often more productive. When a denomination experiences these gifts from God, it should recognize them and do what it can to support and enhance the experience without strangling it. Many churhces are so institutionalized in their thinking that it makes it difficult to do so. (p. 351).