Website
Websites are typically structured to contain/present content that ought to be presented in a hierarchical format. For example, think online shopping - those websites are divided into categories; now, think about a book - most books progress from beginning to end of some particular event or topic. (Keep this in mind...it will come back.)
Blog
Weblogs are typically structured to contain/present content that ought to be presented according to time. For example, remember that dairy you got when you were little...that's a weblog. HUH? I have to post something everyday? No. The typically blogger might post weekly, some everyday or even several times a day, one must remember that those prolific bloggers are earning money from their blog, while others, like me, post when they remember to post or because they decided on the way home that this would be a great post for their blog.
Social Media Page
Social Media Page is typically structured as a stream of consciousnesses or as a personal conversation with a group of friends at a bar/restaurant. For example, one minute you could be talking about politics and the next you could be talking about the surgery your cousin had last week or possibly your sex-life. What's important to remember is that these conversations are occurring in a bar/restaurant. When you're there, don't you hear the neighboring conversations? Another point to consider about a social media page is that is behaves much like a RSS feed - that's really simple syndication; think AP news, they write most of our news but we get that news from other places than AP news.
Overlap
Ok, so that's the basic overall differences, however, there's overlap.
Let's say you are a quilter or a gardener. You want to share your knowledge with the world. Obviously, what you know is structured content. There is a beginning and end. So, one might think a website would be the best possible choice, and it could be. What ultimately decides is your preference - Do you think like a book? In a progression of stages? If you do, then, yes, the website structure would be best for you. But if you think in chunks or want a little more 'freedom' then maybe a blog would be your best choice. But then again, you could decide that a social media page might be the best solution, since you want to have a more personal, stream of consciousness, conversations with others just like you.
Interactions
Each one of these three - websites, blogs, and social media pages - have different levels of interaction with viewers. The social media page - obvious, social - has the most intimate interactions; typically you are expected your 'followers/friends' to either like or comment on what you share, while the website typically has the least (a little to none - your choice) interaction. Meanwhile, the blog is in the middle. Each blog post has the possibility of having or not having comments and how much you, the blogger, interact with those comments is completely up to you.
Summarize
So, which one do you pick? .... Answer the following questions:
How do you think?
What do you want to present?
Do you want to interact with your viewers?
Those three questions will help you decide which will be the best fit for you.
