I read, in an article in Psychology Today, the following:
There are pornographers who do constantly seek out "new, harder themes"--Evil Angel has purportedly found great success with anal gaping videos--but this is a way of attracting and temporarily monopolizing the small minority of individuals who are true novelty seekers. PornHub and RedTube aren't losing eyeballs to such sites: novelty seekers never went to the vanilla tube sites to begin with.
If the tube sites are losing eyeballs at all, it's to cam sites.
It's pretty clear that "losing eyeballs" here is referring to a decrease in the amount of viewers; in other words, "eyeballs" is referring to "viewers".
It is the first time that I see this term used. Perhaps this is because I do not regularly read articles under the themes "websites", "television" or any place where "eyeballs" might come in handy for an author.
I would like to know several things: first, whether or not "eyeballs" is (to a certain degree) commonly used to refer to "viewers". Second, if it is common, how is it used? Can one say: "gaining eyeballs", for instance? Third, for what kind of viewable objects is the term used? e.g. is it exclusively used for internet viewers? Last, and most importantly, does the term imply something negative/positive about the viewer themselves, or is it just purely a replacement of the term "viewer"?