Only when they found something that looked plausible did they actually read the text. Page layouts that made skimming easy fared better than those that didn't. Makes sense that the extra words we normally use to complete a sentence may get in the way of the meaningful words in the text. Removing them, and thus making the text harder to read by traditional measures, may increase scanability. The more white-space, the lower users rated the site in terms of finding things easily, ease of reading, ease of searching, overall appearance, ease of use and productivity.
White space spreads out the info and slows the hunt.
Also, looking at text on a web page is different from looking at text in a newspaper, for example. In a newspaper, the reader can see the whole page at once. This is not true for web sites, which are viewed through the window of a browser. The reader is forced to construct the page in his or her head. Repeatedly, users did not scroll below these lines, even though they did scroll down long pages.