What on earth? A Mac only application, that searches websites anyway? Why is it not a web based search engine?
StackOverflow and GitHub could be formatted with great effort, and stuff like language docs. But not blog posts which differ highly in formatting and need to display images, at that point, you're just outputting the webpage in an IDE. You'd also need a way to index/retrieve those blog posts.
But, you also want actual browser features, as tabs are useful for further reading or comparing various things, or something to look at later.
Just using multiple screen displays is good enough.