A separate note, on the sitemap page concept.
Google loves sitemaps. I have numerous sitemaps on all my website properties which are directories of links to get to the pages on my site. Google *adores* these pages and ranks them highly. Google explicitly asks for sitemaps in their indexing area. I get a lot of Google traffic coming in to my sitemap pages and those pages have low bounce rates. So both Google and visitors enjoy sitemaps.
A linkfarm is wholly separate - a link farm links to external pages. Link farms used to be popular - About.com was originally the Mining Company and it was all about links to various external topic area pages. I was their Wine editor both at the Mining Company and then as they transitioned to a content-based site of About.com. So I saw all of that change happen. A main reason Google began penalizing external-link pages is because they wanted to be Link Central and didn't want other companies competing with them
. So they penalized sites with lots of links to external pages. That's an entirely different action.
So to summarize, internal-linking site map pages are great and rewarded. External-linking link directories are heavily penalized because Google wants to rule the world
.
