What are some alternatives?
When comparing WikiSummaries and Blinkist, you can also consider the following products
Four Minute Books - Making you smarter in 4 minutes or less.
Instaread - Read or hear key takeaways of any book in minutes
Book Summaries - Great books summarized in 5 quotes (or less) so you can get the main idea fast.
12min Reading - Your free habit builder for reading
GetAbstract.com - Book Summaries, Book Abstracts
Hardbound - Illustrated summaries of bestselling nonfiction books