Maybe it's just my browser, but my goodness that font is hard to read. I'm sure the article is quite interesting, but it's beyond my ability.
Couldn't imagine reading log articles on the web without it. It amazes me that 90% of all content-based sites are not designed for simply reading.
Cala-light does look more readable at sane font sizes, but although I'm not a typography expert, its kerning looks bad. e.g. the letter spacing in the word "charging" on the first line, or the sequence "rr" or "oin" just to name a few.
The height of some of the characters, such as t and i, are giving me more trouble than the kerning, even at "sane" font sizes. Words like "contentious" end up so flattened I'm doing double takes on half the words, having misread them. As chrome renders them, words like "to" have height going the wrong way outright, with the t appearing shorter, not taller, than the o!