Unless you’re completely new to web copy you should already know this.
A congested piece of online content is a rejected piece of online content; nobody is going to strain his or her eyes to get the idea you’re trying to pass along.
It’s been stated a hundred times over that readers in the online world don’t read!
I repeat; online readers do not read! Some do, and those are the exceptions to the rule.
They more or less skim: Grazing, to come to a general understanding of what it is you’re saying. And from thereon carry on.
So leave a lot of white space. It encourages the culture fam!