Peggy - Are you asking how to start a blog or are you simply wondering why people blog in the first place?
If you need help with your blog you can pretty much google anything and get some help with your header, graphics, html codes, etc...
If you are wondering more about why people blog, it's a really amazing tool to connect with a huge audience. Any message you want to get across just blog about it! My blog has been a very powerful tool in connecting adoptive families, especially those who are adopting from Congo (which we are). I've also used my blog to help promote the causes of others such as fundraising, contests and promoting their shops or blogs.
Feel free to take a look at my blog and convo me if you want any help. I'd be happy to!
Http://proverbs2412.blogspot.com