What makes Wordpress so Popular?

I recently took a look at the whole Wordpress thing. I wondered why it was so popular and what the whole thing was about.

I am still researching and checking into it all, but I quickly noticed it is a very simple basic script. It is somewhat limited, however that is what it was made to be.

Somethings I like and somethings I don't about Wordpress.

I will continue researching and follow up on this when I more time to evaluate it more thoroughly.