Ebooks

Advantages

• Minimal marginal cost
• Minimal financial risk - you can't print too many
• Lightweight. You can carry a thousand books in your pocket for less weight than a paperback

Disadvantages

• Harder for people to peruse your bookshelf, or see what you are reading. Less chance for serendipitous discoveries

Neutral

• Can't lend them to other people, no second-hand market (bad for readers, good for booksellers)
• Piracy much easier (good for readers, bad for booksellers)
• Authors don't need a publisher, can easily self-publish through Amazon. Good for authors, bad for publishers, risk of Amazon establishing a monopoly (bad for authors)