Ultimately it makes a weak reference, at best it's just a personal reference since you have not done business with the person, if someone calls and you answer truthfully that you don't really know someone it would be a big negative, giving the appearance that they fabricated or bought a reference.

I have a bad habit of offering people to use my name as a reference at my job whenever I get into small talks with people when they ask where I work. Even people I just met or met before a few times. For example, today this guy at a local grocery store I go to alot asked me if he could use my name as a reference and I said yes and gave him my name and number. Does this look good or bad in regards to how my company views me? What are the negatives and positives of it? I dont personally know him but I thought it would be a good way to promote the company(since were always hiring). Any response would be appreciated, thanks!