What I like about Hubpages is the enormous interaction between the Hubbers - like my being able to sit down and write an answer straight off the top of my head to a question like yours. On Hub pages there seem to be an awful lot of really interesting people ranging from people just starting out in 'writing for fun' and those who, like myself, have been into it for years.
It's doubtful if any of us will make any really big money on Hubpages. I know I haven't. So I'd say forget about it as a money-maker. But if you just want to communicate with other people, it's the way to go.
There seems to be no restrictions on what you can write about, providing of course,you don't deliberately write stuff which offends.
I'm pretty sure you'll get a lot of answers to your question.