In early 2005, Google implemented a new value, "nofollow", for the rel attribute of HTML link and anchor elements, so that website developers and bloggers can make links that Google will not consider for the purposes of PageRank—they are links that no longer constitute a "vote" in the PageRank system. The nofollow relationship was added in an attempt to help combat spamdexing.
I have not at all seen the results I would expect in terms of page rank throughout my site. I have almost everything pointing at my home page, with a variety of anchor text, but my rank is 1. There is a page on my site with 3, though, and a couple with 2, so it certainly is not all about links; I do try to have somewhat unique and interesting content, but some of my strong pages are default page content. I will explore the help forum. (I guess these comments are nofollow :P) I would not mind a piece of this page rank …
As Google becomes more and more sophisticated, one of the major cores of their algorithm, the one dealing with links (called Penguin) aims to value natural, quality links and devalue those unnatural or spammy ones. As a search engine, if they are to stay viable, they have to make sure their results are as honest and high-quality as possible, and that webmasters can't manipulate those results to their own benefit.
Description meta tags are important because Google might use them as snippets for your pages. Note that we say "might" because Google may choose to use a relevant section of your page's visible text if it does a good job of matching up with a user's query. Adding description meta tags to each of your pages is always a good practice in case Google cannot find a good selection of text to use in the snippet. The Webmaster Central Blog has informative posts on improving snippets with better description meta tags18 and better snippets for your users19. We also have a handy Help Center article on how to create good titles and snippets20.