How do bloggers/journalists/writers use someone else's news article?

I'm researching how writers of all kinds use an existing news article for their own writing. For example, an online newspaper publishes an article, I read it, find it interesting, and want to write my own reaction, thoughts, expertise, etc regarding it. What methods or tools are available for using that news article as the basis for my own writing?

I see:

• Tweet the article link and write thoughts in the tweet
• Write a blog post with copy & pasted original quotes and links
• Use article's comment section..?

Are there other preferred or creative methods? What do you do for this?