If nothing else, the NFL is great at scouting players and getting to know them personally. There are three college All-Star games which include the East-West Shrine Game, NFLPA Bowl and most importantly the Senior Bowl.
Each of these allows coaches to get close to players and see what they are like off the field. The Senior Bowl is coached by a full NFL coaching staff and many a player on their All-Star squad ended up being drafted by their NFL staff which had coached them for a solid week.
In March, the combine is held every year in Indianapolis.