Some related posts from Technorati and Google.

[Reality SEO - Search Engine News, Commentary & Ranking] Torpedo & Sink the Ship "SS Search Engine Rankings": As his SEO I should have realized that the top rankings of this already optimized page were in danger when his first sentence referred to the existing "Dusty, tired old page, that just isn't getting enough sales." That page had just been optimized for search engines about 6 months previously, and went from page 10 (invisible) or so of the Search Engine Results Pages (SERP's) to the top three on the first pages of all three major search engines virtually overnight after a few tweaks to gain traction from a popular movie reference to his product.

[Stephan Spencer's Scatterings: Web Marketing Blog] What’s wrong with Google Sitemaps: Armed with this information, Googlebot will be able to not only eliminate duplicate pages but also intelligently choose the most appropriate version to save in its index and then associate with that page the PageRank of ALL versions of the page. The days of session IDs killing a site’s Google visibility would be over!

[SEO Tips] Search Engine Crawlers and Dynamic Web Pages: character, major search engine spiders can crawl that page well. For example, Google can index and store a page's URL as (http://www.examplesite.com/product.asp?id=12345).

 [Blogbusinessworld.blogspot.com] Blog Business World - Marketing, Public Relations, Search Engine ...: Whether you choose, DMOZ, Yahoo, JoeAnt, Gimpsy, Zeal/Looksmart, or one of many lesser known directories, inclusion in them will get your website crawled by a spider. Since the various internet directories are crawled on a very regular basis, you can be almost certain a spider will travel to your website.

[Searchenginegenie.com] SEO BLOG: An other possible reason is the site is banned from the search engines for any particular onpage factor, In that case search engines periodically checks to see whether the onpage spam tactics is removed and as soon as they see the spam being removed they might reinclude the site into the index, So for people who are complaining that their site was previously indexed and listed in google but suddenly it disappeared from the index and googlebot keeps visiting the site it is good to look at your onpage work and see if there is any spam tactics like hidden text, cloaking, keyword stuffing etc,

 [Forums.lilengine.com] Where does Google bot start crawling?: While I haven't seen any widespread evidence, I do notice that my sites that are listed in DMOZ tend to get crawled/indexed at a quicker pace and more thoroughly than my sites that are not included in the directory.

Reflected tags on Technorati: Blog, SEO, SEO Files