CSE wants you to list sites that you want to search from. Of course, you can't default to '' or '.'. They even stated that '.com' and '*.org' etc. won't return any results. That's unacceptable. Secondly, given you could configure it meaningfully it seems it's pretty hard to configure your browser's search bar to use this CSE instead.
And that's what I think most people use for searching. At least I do.
Facebook got it right this time: with each post, there's an option to hide that post, that person, that application, or that site which posted the post. One click that means "don't show stuff from them anymore": that's what Google needs, too.
By this I mean I added it to my browsers, but I still use regular Google search daily. If the results is laden with bogus sites, then I switch over and start again, weeding if necessary.
Initially I thought I'd use GCS all the time, but it lacks the Google menu (Images, Maps, etc) which comes in handy more often than I expected. I use GCS most for code/development related searches.
Business rule bug...
http://news.ycombinator.com/item?id=2075437
It's not so much that it's a knowledge vacuum, just that someone didn't read the whole thread before replying.
If you go to the CSE website and select 'Advanced' and then download annotations, you can export the list of sites you've excluded.
Further you can make the exclusion list ("annotation list") into a feed - so it is entirely possible to implement the kind of user-generated blacklist of sites which has been discussed here.
GCS is really easy to set up - takes only a few minutes. I spent the most time hunting down rouge sites - which was actually kinda fun and cathartic.
Big tip: keep an easy-to-get-to link to the GCS Sites Control panel, so it's easy to add new sites. I've added ~40 more in the past two months.
Alternatively I will stick to my plan to change search providers. One way or another.