This is a great question. When it comes to blogging it is really important to know who you are as a blogger and where you fit in.
I think for my blog, it is the uniqueness that we are all five of us are sisters but are best friends at the same time. The fact that between the five of us we are at a lot of different stages in our lives, so you never really know what the next post will be about.
I think in my blog is unique because it's not just for entertainment it's also helpful. I know a lot of wedding blogs provide lots of pretty pictures but there's no content to actually help you plan your wedding. I think that's why mine is so great, you get the best of both worlds, useful content as well as the pretty pictures.
Eeeh... nothing? In all honesty - I'm not a writer. If people come to my site it's mainly because they want to see my art and pixels. The only reason why I have a blog on there is because I'm to lazy to make a separate site for it XD