As the technology and usage of the internet is evolving around our daily lives, web sites' main purpose also shifts considerably from "what" you are representing to "how" instead.
Importance of User Experience is now significant, which usually determines users' bounce rate and the total amount they spend on a website. If a content is presented in a slick, minimalist design and smooth colors, we tend have a positive feeling about it. Then comes the quality of the content.
In an era like this I find it unacceptable to see a website where its design looks attractive, but not usable when it comes to processing of the content.
I am a consumer. I would like to enjoy browsing a blog, magazine, or any website with as less disturbing as possible graphical content (yes, I am talking about Ads), where I should be also able to consume the content with the same comfort. My main complaint against this is; contrast rates.
Minimalism is not about lowering the contrast rates.
On the contrary, it makes reading long text extremely painful and easy-to-be-distracted. WCAG 2.0 indicates that:
The visual presentation of text and images of text has a contrast ratio of at least 4.5:1
Although I still find 4.5:1 rate insufficient, if all the websites were to consider changing their styles accordingly, I wouldn't probably need to use a tool similar to Readability to - well, increase the readability.
There exist a very simple web tool to test the contrast rate you are using here at WebAIM - so a website should have at least a rate of 4.5:1.
Next important aspect is choosing a font, though this needs another post to cover the subject thoroughly.