Blogs also work great with search engines, why? Because blog are rich content websites and search engines love these types of websites. If you decide to create a blog, I strongly recommend you to add content regularly as search engines also love the fresh content.
To create a blog you have tow options, the free option and the paid option. The free option is easy and fast, you just need to create an account with Blogger.com. If you have an account with Google, you don't need to create a separate account for blogger, you just need to create it through your Google account.
Installing a free blog at Blogger.com is very easy and will take only some minutes to create your own blog. You can also convert your blog to a registered domain name for free. You can also use your blogs at Blogger to earn from Google Adsense. Blogger is my number one recommended platform to create as many blogs as you want.
Another free blog platform is WordPress, at WordPress you can see some professional features like nice themes, professional category section, calendar and other cool features. But you can't use Google Adsense program as WoredPress doesn't allow you to edit the template through your free account. WordPress is my second recommendation to create a free blog.
The second option is to host your blog at your own hosting account. There, you can install wordpress under your own domain with only some few clicks, and you can easily edit the template to add your advertising codes like Google Adsense. I'd recommend you to get a hosting plan from Host Gator as you can easily build your own blogs in seconds.
How to promote your blogs:
1- Submit your blog to free blog directories.
2- Exchange links with other bloggers.
3- Submit free articles include links to your blog.
4- Add content in a regular base.
5- Keep in touch with your visitors by giving them some free tips and gifts.
6- Add feed subscription option by FeedBurner to save your keep your visitors coming back again.