The answers to both need to be different because the requirements are different.
For personal use, either Blogger.com or Wordpress.com give you access to popular blogging platforms and lots of tools and layout options that allow you to do pretty much what you want. If you want to share thoughts, ideas, photos, etc they both work well. Of course there is also Facebook of what you're looking for is interaction. All three are completely free of charge.
For business needs it's perfectly possible to use the same platforms. The problem if you do is that you are putting what is potentially your most important business building tool under the control of someone else. Blogger (owned by Google) could change the rules at any time - as could Wordpress.com - and suddenly you might not be able to run your online business in the way you wanted too.
I couldn't possibly run a business with that weakness hanging over me. Like many people who write here at Hubpages, it's not my only source of income - too many eggs in one basket. Same if you run a business website through Blogger or Wordpress.com - it's free but someone else can change the effectiveness of your business overnight.
The solution is to have your own hosting, which to start off with would cost you no more than five or six bucks a month (I use Hostgator but there are dozens of similar hosts). Then you get your own domain name for just over ten bucks a year and then install Wordpress as the platform. This is a self-hosted version of the program behind Wordpress.com, yet with much more power and flexibility available. It gets better - because the Wordpress program is free, as are thousands of themes (templates) and plug-ins that help functionality. Have a look at Wordpress.org for more details.
For under ten bucks a month you have hosting, your own domain name and a powerful, flexible platform that is inherently good for SEO. What's more you have control of probably your biggest business asset. If you can't afford ten bucks a month, you need to have another look at your business model.