This is something I've been thinking about for a while (years, actually), and it's come up again recently with all the talk on stats and my attempts to analyse my own. In particular, how the viewing stats from webcomic readers compare with those coming from sites like WFG/TWF. Basically, there's a pretty striking difference to how they behave (and, indeed, the raw numbers). I'm basing this on figures from both my current serial (which hovers around the five thousand views/month level) and my old one (which would bounce from fifty to a hundred thousand a month).
Boiling it down to percentages, people from webcomics are more likely to stick around, but even those who don't will read at least a short way into the story. On the other hand, readership from webfiction sites drops sharply within the first couple of (story) pages (from the first page especially). Now, I'm not sure this is because the webcomic audience is more curious, coming from a visual medium to a written one, or if webfiction readers have very specific tastes/expectations. Maybe it's both. Maybe it's neither. The first page of my serial involves animated text. Are webcomic readers more open to something visual? It's hard to draw conclusions when I have only my own analytics to go on
Something else I've noticed is that breaks in my schedule don't lead to drops in readership. Again, this is based on stats from both old and new sites, both of which have a high chapter-to-chapter retention, even during those times I've missed an update. Ending major story arcs can see that retention drop as low as 90%, but not updating for a week? Nope. Looks like people just pick it up later on (I've noticed a big trend in binge reading across both serials). So, again, is this a demographic thing? Are certain audiences more likely to ditch a series for missing an update? Or are webcomic readers simply used to irregular schedules and binging the archives?
At the very least, however, I think this demonstrates the importance of looking beyond what you believe to be the "obvious" audience for your serial. I've never really done any promotion around social media or communities like Reddit, so maybe they would offer up different patterns, too. It would be interesting to get an idea of what the current "webfiction demographics" are, though, at least those coming from and using sites like this and TWF, so it can help people searching for their readers (and bolster the hopes of those who got themselves listed and saw little returns from it).