Yes. Yahoo! automatically adds a robots.txt file to the root directory of your domain (for example http://www.merchant-store.com/robots.txt*) for pages built using the Store Editor. This file outlines all of the directories that should not be crawled by search engines. This file is not currently editable by merchants.
* This example URL assumes the merchant has set up the domain traffic option to point to the store side of their Merchant Solutions account.
If you are using the Web Hosting portion of your account to build pages, you can add a robotos.txt file in one of two ways: