Customers will automatically find the Index page when they type the main part of your website URL in the browser's address bar. For example, http://www.yourwebsite.com. The page allows your customers to signup with a credit card, an on-line check, lookup account information, contact CCBill customer support and access your members area. The look and feel of the Index page can be customized.
For some large groups that are distributed across many different Tree of Life pages, it may be useful to have an index page with links to the most important taxa. For example, it takes meandering through several pages to get to some of the insect orders. So in order to facilitate navigation to certain lineages, there is a link to an index page on each of the main insect pages that takes you to an alphabetical list of orders. This would allow people to quickly find a group without having to search through the Tree.