Google Answers - What's an SEO

What's an SEO? Does Google recommend working with companies that offer to make my site Google-friendly?

(Information provided by Google.com)

Search Engine Optimizers

SEO is an abbreviation for "search engine optimizer." Many SEOs provide useful services for website owners, from writing copy to giving advice on site architecture and helping to find relevant directories to which a site can be submitted. However, a few unethical SEOs have given the industry a black eye through their overly aggressive marketing efforts and their attempts to unfairly manipulate search engine results.