On the other hand, a collective niche ( i.e https://www.forumine.com ) Is set up to cut across all aspects of a user's interest. In this case, the interest can include sports, technology, entertainment or other "day-to-day" aspect of human life. A pro in this case can supersede the pros of a targeted niche in sense that visitors will always find their area of interest.
That being said, Most forums seem to embrace the concepts of targeted niche as opposed to the collective niche forum setup in recent years. What are your thoughts?