Incentivize SEO for fine granularity (punish blogs that spam too many common keywords) and provide more filtering tools to users. Former is likely already done

Incentivize SEO for fine granularity (punish blogs that spam too many common keywords) and provide more filtering tools to users. Former is likely already done for many popular platforms along with many other tricks so you would want to have experienced people for that part. For filtering tools a good one would be adding a way to have filter lists against spammers and generally just more options to how you want to refine your search. I get that Google Search allows you to type some special keywords but I'd rather it be more user-friendly.