What does it mean to "stuff the site?"
Answer: With millions of websites competing for search engine ranking, Web developers are always trying new techniques to get their websites listed near the top. One approach is to "stuff the site" with meta tags and content that are intended to make search engines list the site higher in search results for relevant keywords.
Stuffing the site may involve adding long page titles and extended meta descriptions. Some developers may also add numerous terms to the meta keywords tag. A developer may also stuff a site with repeated words and synonyms that are relevant to the page's content in hopes of gaining a higher search engine ranking.
However, most search engines are advanced enough to detect the site-stuffing techniques employed by some webmasters. So instead of improving search engine ranking, stuffing a site may be a waste of time, or worse yet, it can actually hurt a site's ranking. Therefore, the old mantra of designing a site for users and not for search engines is the best advice to follow.