The site used to have a clever internal system which monitored the keywords sending natural search traffic and then added them to the page automatically to make the page seem more relevant than before and therefore get higher rankings. It seems that this feature has now been turned off.
We made some changes that will have a short-term impact on traffic. Primarily: 1) improving our copyright filter, which keeps unauthorized content off the site and 2) reducing the aggressiveness of our SEO, which reduces total traffic in the near term but increases the relevancy of Scribd links in search engine results
Displaying recent search queries used to find a page is a feature that might be useful for users especially if you use the keywords in a tag cloud to help determine what the content is actually about – probably more useful than relying on users to tag their own content. I can’t imagine why Scribd would decide to improve Googles search results without being forced into it by Google.
It’s interesting that Scribd has raised over $10m in funding based on big traffic rises thanks to SEO which is normally way down the list for startup companies.