I used to blog on an online dating network, and it was awesome, I met a lot of great people. We had our own little blogging community. But here are the reasons why it shouldn't happen.
If your blog gets real popular on THEIR site, then you are stuck! You can't put them onto your own domain name. They aren't very mobile once they are on there.
Your blog will start to get boring after awhile when you realize that you can't change your blog to your own design. You can't make it into your own style, you are stuck with the social networking's style.
The only people that will view your blog are going to be the people that use that specific social networking site. You are totally limiting yourself to so many more people liking your blog.
You have no way of knowing how long the site will remain active. One day you could go to sign in and your site could be completely gone. Your blog will be lost forever!
Chances are you won't be able to monetize your blog but more importantly, the site is probably making money off the writing you are doing. So you are lining someone else pockets with your money!
Great list...even if I don't entirely agree. I mostly agree but also think that using someone else's site is a great way to learn as long you still own the content you create...different rules for different sites, so read the terms of service :)
select one here...