The relationship between SEO and the search engines
Due to the high value and targeting of search results, there is potential for an adversarial relationship between search engines and SEOs. In 2005, an annual conference named AirWeb was created to discuss bridging the gap and minimizing the sometimes damaging effects of aggressive web content providers
Some more aggressive site owners and SEOs generate automated sites or employ techniques that eventually get domains banned from the search engines. Many search engine optimization companies, which sell services, employ long-term, low-risk strategies, and most SEO firms that do employ high-risk strategies do so on their own affiliate, lead-generation, or content sites, instead of risking client websites.
Some SEO companies employ aggressive techniques that get their client websites banned from the search results. The Wall Street Journal profiled a company that allegedly used high-risk techniques and failed to disclose those risks to its clients. Wired reported the same company sued a blogger for mentioning that they were banned. Google's Matt Cutts later confirmed that Google did in fact ban Traffic Power and some of its clients.
Google has enforced webpage restrictions for years, such as for hidden-text (background and foreground colors the same hue); in 2006, Google could punish a non-standard website by blocking search-results, automatically, the next day for 30-35 days (or longer), pending a reinclusion request, and if reinstated, revert the index to old/expired/deleted webpages from a year earlier, delaying the re-indexing of the current website for a total of 2-4 months.
Yahoo! and MSN Search do not automatically punish entire websites for small amounts of accidental hidden text. Google's market share of daily searches has fallen rapidly from 75% to 56% over the past few years, as other search engines find many valuable webpages that Google has banned and cannot display due to Google's severely limited index. In early 2006, MSN Search typically re-indexed small websites every 14 days, and Yahoo! also re-indexed quickly, much faster than Google, but all three MSN/Yahoo!/Google could require more than a month to index a new page (new file name) on an old website.
Some search engines have also reached out to the SEO industry, and are frequent sponsors and guests at SEO conferences and seminars. In fact, with the advent of paid inclusion, some search engines now have a vested interest in the health of the optimization community. All of the main search engines provide information/guidelines to help with site optimization: Google's, Yahoo!'s, MSN's and Ask.com's. Google has a Sitemaps program to help webmasters learn if Google is having any problems indexing their website and also provides data on Google traffic to the website. Yahoo! has SiteExplorer that provides a way to submit your URLs for free (like MSN/Google), determine how many pages are in the Yahoo! index and drill down on inlinks to deep pages. Yahoo! has an Ambassador Program and Google has a program for qualifying Google Advertising Professionals.