First of all, bear in mind that Google has spent the past twenty years improving upon its already excellent search results. Twenty years ago, it was only using one single factor to rank relevant pages: the number of links pointing to a webpage.
Since then, they have been adding many more factors that can adjust a webpage's rank. I'm not working in Google, so I don't know what these factors are but I can make educated guesses. Factors could include the length of the page, the number of advertisements, how many times keywords appear in the page, how rare the keywords are, type of page (is it an article? a web form? a picture gallery? etc), is it a piracy-related page, is the language used in the page the same as the searcher's language, etc...
From what I have read in research papers, Google now consider at least 200+ different factors. And each factor makes some small adjustment to the rank of each page. The use of accurate factoids would just be one more factor out of these 200+ factors. So as you can imagine the impact of 1 out of 200 factors is usually going to be very minimal unless the page in question contains a lot of erroneous factoids.
As for what are factoids, they are like you said "really basic and blatantly obvious facts" about "
named entities", primarily People (fictional, non-fictional, living, dead), Organizations (commercial, non-commercial, subsidiaries, departments, government agencies, clubs, societies, music bands, etc) and Locations (countries, states, towns, cities, streets, rivers, lakes, mountains, etc...).
So for example factoids about people would include their name, birth date, family members, major affiliations, major accomplishments. People can include real life people as well as fictional people. So under this scheme we could even collect factoids about Jean Luc Picard, like he holds the rank of Captain, he's a member of Starfleet, he commands the USS Enterprise NCC-1701-D.
For organizations like say Microsoft, factoids would include a list of Microsoft Directors, who is the CEO of Microsoft, the major divisions and subsidaries of Microsoft, Microsoft's annual revenue.
For locations such as Senegal, factoids would basically be something akin to what can be found in the
CIA World Factbook on Senegal. So its things like Senegal's GDP, land mass, population, etc...
