I think it really depend on how you look at it . but it is a really good way to get your self expose to what ever you want to do like getting a job or thing of that nature. so over all I just think it is just how you use your blog . if you are use your blog for the right reasons then you will not have any reason to fret . also staying true to your first real motives for your twitter or blog .
personally I like blogs because the fact it really gives me a chance to express my self in a positive light . and let people see how wonderful of a person I am . and it is a broader band then twitter so it really just let me go further in-depth with all of my chat and is very easer to under stand. but at the same time it is easer to get in contact with all of the celebrities in the world. and over all just both gives you a great way to promote you self to give you a great chance at marketing your self .