I think that is quite a large part of it. From what I have seen many people don't really filter their privacy settings on Facebook. Most relationships develop a

I think that is quite a large part of it. From what I have seen many people don't really filter their privacy settings on Facebook. Most relationships develop around a shared interest or activity and each develops at its own pace dependant on many different factors. Accepting a friend request for a lot of people would be like you going up to them in class and saying 'Hey, I've seen you around. I'm dvt.' and the person responding by pulling out their phone and handing it to you to leaf through their photos, check their calendar and see who;s numbers they have. Google tried to address this with circles, which Facebook responded to and implemented a similar solution, but I think most people just don't like to classify their 'Friends' when first accepting a connection and are very unlikely to reclassify them later.