Blogging is such an infant genre. It's changing the way we write. What we write about. Our audience. And the way we interact with our readers.
Victor Hugo: Would've lost his audience with his intricate sentences and terribly long paragraphs. Not to mention that he could stay on one topic for about sixty pages (see description of Paris in The Hunchback of Notre Dame). Blogging would not be a good genre for him.
T.S. Eliot: Would've never gotten any Google page rank, due to having far too many outbound links on his home page. You know, the footnotes and all. But probably would've found a niche audience regardless.
Shakespeare: Now here's a blogger waiting to happen. He would've broken his posts up into acts. He would've created his own Memes like "Soliloquy Saturdays" and "Sonnet Sundays." Perhaps "Tragic Post Thursday. And who would dare leave a snarky comment on his posts? Because he's the insult and comeback king!
J. R. R. Tolkien: Blogger spell check would not tolerate his penchant for using Elfin languages and made-up words. Samwise Gamgee? Frodo? Golum? There would be red squiggle lines underneath every other word, and Tolkien would spend his time clicking "ignore word" over and over. (same for e. e. cummings).
Thoreau: Might have been a good nature blogger, but probably wouldn't have an internet connection where he lived.
Samuel Johnson: Would get the most pingbacks as other bloggers would quote his posts extensively.
Jane Austen: Would've had a dating and relationships advice blog.
What do you think other authors' blogs might have looked like?