I think one or two people have tried it in the past. Not very many people find them interesting to read though... Probably because, with websites like blogger, livejournal, twitter, facebook, tumblr, we already start to feel like we are being inundated with peoples' lives. Too many people seem to like to online blog in the style of "my life is horrible..." or "i am completely in love with person x who I have no hope with cuz I am completely immature" or "here is every unnessecary detail about what happened in my day today." I guess it depends on how you pulled it off. If you can do it in a way that seems interesting, mature, enlightning, etc. Then you could probably be successful regarding readership.