Search engine optimization has been around for about as long as search engines have. It's hard to imagine SEO before Google with its current market share domination, but as early as the mid-1990s, marketers were thinking about how to make their products as findable as possible on the web.

The Birth of SEO

In the early days of search, Yahoo! and its cohorts were run like Yellow Pages services: website owners submitted their sites for indexing, and search engines did their best to match up pages with search queries. Most ranking criteria centered on keyword density—did a given keyword show up in prominent places on the page? How many times did it occur in the page's content?

It wasn't long before website owners caught on to search algorithms and began to tailor their sites to meet search engines' criteria. Search engine optimization was born! This meant that the first generation of web marketers had new tools to help get their content in front of the growing consumer base that was the Internet. It also meant that they could, through reverse-engineering the algorithm, easily create hundreds of pages that ranked for search terms without passing much value along to the searcher.

These were the first skirmishes in what would become a battle that continues to this day. Search engines try to create spam-proof algorithms that surface the best content to their users, while marketers struggle to get their sites to the top of the rankings—sometimes, ...

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