I experienced the same effectiveness (95%-99%) of getting the "guy/gal reading the newspaper" to volunteer for the study first hand. Although, this was more foc

I experienced the same effectiveness (95%-99%) of getting the "guy/gal reading the newspaper" to volunteer for the study first hand. Although, this was more focused in cafe environments. Our team was trying to get beta users signed up for a location-based iphone app in the Boston/Cambridge area and most people reading newspapers in coffee shops or cafes are frequently willing participants. I even noticed that 7/10 times these people will engage with you in conversation regarding feedback/UX improvements etc. In parallel with Rodyancy's experience, some of the user feedback was arbitrary (one guy started comparing our application to time/space continuum theories...etc) but nonetheless, I would advocate approaching the newspaper guy/gal as they are already on the knowledge quest and usually are more open-minded. Oh, and avoid the book/textbook readers. These people are either really engaged in novel (imagine tapping on someone's shoulder during a movie) or are stressed-out students.