Matt Cutts [1], head of Google's Webspam team and an engineer who's been working on the problem for eight years, offered some tips about combating it during a speech at the Web 2.0 Expo here.
• Use captcha systems to make sure real people, not bots, are commenting on your site.
• Reconfigure software settings after you've installed it
• Employ systems that rank people by trust and reputation.
• Don't be afraid of legitimate purveyors of search-engine optimization services.