Yahoo has announced that rolled out an index update on October 10, 2006. Marketers should notice a change in some rankings and a shuffle of the pages in the index.
Matt Cutts, the well known engineer at Google, has also announced some updates going on at Google. Google just recently exported PageRank info, so people should be seeing some changes in PR as viewed in the Google toolbar. The rest of the changes at Google are infrastructure changes and deal with the Supplemental results and making sure that "site:" queries are more accurate. Google has also pushed out new "link:" query information to reflect more backlinks pointing at sites.I also want to mention the recent upgrades to Yahoo's Site Explorer. This program is a simpler and less enhanced version of Google's Sitemaps program but is improving slowly. Check it out and watch for future enhancements. I also recommend converting your Google Sitemap to a Yahoo Sitemap and submitting it to Yahoo.