"I am a designer....I cannot get my head around databases. "
On your other note:
Just think of databases as an easier way to manage data. The database takes care of all the details for you instead of having to deal with all of the data manipulation manually. A database is like a file cabinet compared to a pile on your desk.
If you are talking about WA using blogging software for a blog - that makes perfect sense to me. Why recreate something from scratch when someone has already done it well, and is giving it away for free?