My sites traffic increased a shit-load (30%) on around the 14th of this month.
I have not changed the content, but at the start of the month I read about how Google said your site should look like an 'apple product', so...
I tweaked the .css and php on my wordpress themes, and I have to say they now look smooth as f**k! I also optimised my theme for speed, minified everything, got rid of all unused .css and speeded up the sites by almost double.
I also have no ads above the fold, but Google have been talking about this update coming for a while now.
The results of this have been astounding, more visitors, bounce rate used to be in the 70% range, now it's around 45%, considering that I have not changed the actual content at all.
I really believe that if you tweak your sites layout and theme to be stylish, user-friendly and unique it will make a positive impact on your bottom line.
I'm one of the lucky ones that was one step ahead of this update.
P.S. 1% of sites is still roughly over 3,500,000 websites.