The basic principles of search engine optimization - how sites are designed, written and coded - have remained relatively unchanged for years. Marketers know that to achieve high natural search rankings they must design keyword-rich sites (including body copy, meta tags, title tags, directories and file names), maximize links in, and accommodate "uncrawlable" sections (e.g., images) with alternative text. But the advent of social computing has brought a new technique to the marketer's SEO toolkit: blogs.