Your blog is your online journal and soapbox.
You can write anything you choose. Many users post trades while others simply evaluate companies looking for buy and sell candidates. Some users just write commentary on their daily routine while others simply write what they had for lunch. It's up to you to decide what you what you have to say.
In addition to writing your notes directly on Blocks.com, it also supports the MetaWebLog API letting you publish to your blog from any Blog editor like Live Writer.
Whatever you have say, Blocks.com will give you the virtual pencil and paper to say it.