Google, Yahoo, MSN add SiteMap Auto-Discovery
Google, MSN ,Yahoo and ASK have announced uniform support for a sitemap submission to all search engines. Simply by adding the following line of code into your robots.txt file, the engines will know where your sitemap is located on the server and pick it up on their routine crawls. Sitemap: www.example.com
/sitemap.xml Obviously, replacing the URL above with the URL of your sitemap index file. Neither of these announcements was specific but looking at the example provided by Yahoo this does appear to support SiteMap exported into an XML file, not just an HTML file.
What are supplemental results?
If a page is shown that is in the supplemental results, Google indicates this in their search results pages (SERPs). It doesn't mean that your page or site is banned or penalized. More often than not, pages that are similar to other pages (or complete duplicates) are the ones that show up in the supplemental results. It's generally not something to worry about unless tons of the pages on your site start showing up there. When that happens you'll need to figure out why and fix whatever might be causing the problem.
What is a link farm?
There are many definitions of a link farm, but I like to go with the traditional one. That is, a link farm is a set of websites that have all decided to link to each other. It's basically done through a links page that every site from the link farm is required to upload to their site. Every time a new site is added to the farm, it would get added to the links page for everyone to re-upload. There have been hundreds of variations on this basic idea through the years. Suffice it to say that you want to stay as far away as possible from any kind of linking scheme whatsoever. Especially one that requires you to link to sites that you might not really recommend to your target audience.