I love “what’s the difference between a duck?”

In some ways, this is a question of “what’s the difference between a duck and a mallard.”

A website is generally a static property that does not change very often. You put up your pages, and short of some copy changes as a result of changes within the company, it stays the same. Google gets very bored with these.

A blog, on the other hand, is a very public journal or diary. As you put up new blog posts, the entire nature of the blog changes, and Google gets all squidgy and happy, because they have new content to digest on a regular basis.

A blog can be a website, thanks to WordPress’ functionality of letting you add pages, and then setting one of those other pages as the front one. However, a website can have a blog within it, but is not a blog in itself.

So, to paraphrase George Costanza, are all blogs websites? Yes, they are, but are all websites blogs? I don’t think so, my friend.

websites are used to facilitate communication from a source for mass consumption.

Yet blogs are used for the same things. @deairby I think this was your question was it not?

The Application that runs it.

To disagree with @davidwalizer & @erikdeckers the only difference between a blog and a website is the application that runs your site. 

Remembering that a blog was originally a web log, just an html website page that was updated on a regular basis, so the newest was on top. the only change from the web log of old and a blog today is that application that runs under your text.

“A website is generally a static property” like your old blog posts
“A blog, on the other hand, is a very public journal or diary” not really – is SME a journal or diary? Stretch and say journal? Naa.
“A blog can be a website” and a website can be a blog – in that you can use WP to build a bunch of static pages. In fact is it easier to build a website that looks like the pre-blog websites using a WP theme than it is with anything else.