You probably know Arvid Kahl from the many top books he’s written about entrepreneurship. Did you know he also runs a SaaS? PermanentLink makes sure the links in your eBook don’t break. If for whatever reason a link becomes obsolete, PermanentLink will find an archived version of the web page and display that content to the user.
Super useful if you make a lot of infoproducts and don’t want to be updating your links all the time.
(also, it’s inexpensive and has a free trial so…)