But why is Google even dealing with spam? What if they (or someone else) curated top websites for a given category? For instance, when I search for a programmin

But why is Google even dealing with spam? What if they (or someone else) curated top websites for a given category? For instance, when I search for a programming-related term, I already know that I want to see the answer on either Stack Overflow or one of a few reference documentation sites. It is possible that some other site could have the answer instead, but in practice the random sites that often show up at the top of the results are usually SEO spam. A search engine that figured out or let you select the semantic space you are in and then promoted known websites - maybe ones you curate yourself! - would be a big improvement. Of course you can always hardcode the site you want in the Google search results but this is hacky and not very expressive.