The one thing I wish that Google offered would be the ability to blacklist sites for a period (coud be fixed - say 6 months).

So damn annoying when the top search results all lead to shitty SEO-optimised sites that use a whole page to blather on and on, leading to a tiny information nugget at the end. No value, just excellent SEO scamming.

As these scam artists get better and better at this, Google gets less and less useful.

When I see a site like that, I can be quite sure there is no value to me from that site. I want to blacklist it - not forever (though I'd settle for that) but so I don't see it in search results again.

The crazy thing is that this could even be a benefit for Google themselves. They could aggregate these signals and use them to identify SEO scammers, since their algorithms clearly can't. I'm sure that Google aren't happy with the lacklustre performance of their search in modern times.