Things are about to get better.
"The Wayback Machine, a service used by millions to access 19 years of the Web’s history, is about get an update. When completed in 2017, the next generation Wayback Machine will have more and better webpages that are easier to find. The Internet Archive, with generous support from the Laura and John Arnold Foundation (LJAF), is re-building the Wayback Machine which currently offers access to 439+ billion Web captures including Web pages, video and images."Read the details of the planned improvements at https://blog.archive.org/2015/10/21/grant-to-develop-the-next-generation-wayback-machine/. The one that caught my attention is:
"Finding websites based on keywords. While indexing all of the pages in the Wayback Machine is beyond what we can do, we will index homepages of websites so that patrons won’t have to enter specific URLs to dive into the Wayback Machine."