Chances of publishing a webserial?

This is a tough one. The prevailing wisdom of publishing says that no trad pub will touch a property once it has been published; doubley so if it's still available online. That said, the times they are a changing, and I suspect that rule isn't quite as hard and fast as it once was. I'd say it depends on your planned avenue.

Big 5/publishers who require agents are probably a non-starter. That's the oldest arm of the industry, and the slowest to adapt to changes. Odd of getting a serial in with these folks are... well nothing is impossible, but I'd brace for an extremely uphill battle.

Small presses, on the other hand, might be more open to the idea. These are ones without the reach and connections (don't expect to be in major bookstores) however they tend to allow non-agented submissions and more open to newer ideas/mediums such as serials. This will still be case-by-case, but is a much more attainable publishing goal for a pre-posted work.

Like DrewHayes says, it's a tough one, and a bit uncertain in modern times.

But, the rule of thumb is: Can publishers make money from it?

For big publishing, the answer will be no unless you get a viral hit like "Fifty Shades of Grey." For small publishing and presses, probably only if you find one that really likes your material or if it fits with their existing lineup. But, big or small, you have a lot better chances if you have proof that your work was a hit and has a pre-built market. Being the same reason YouTube stars get book deals.

I started asking myself a bit of a side question to this though: What does publishing even mean anymore? Is it about having a printed copy? Making money? Is it about the chance of getting your work read by more people? This kind of question is more important to me, especially because things like money and readers can be more guaranteed online.

If it's more about the societal stamp of approval that being "published" gives you, then I'd say don't release it online, but continue building up a name with other works related to the big thing. Submit short stories and essays to magazines and zines and small pub houses. Then submit to agents and find one that syncs with you. This is about a five to ten year investment, but it's also the most direct and promising route to traditional publishing without some sudden chance of fame or landing just-the-right agent.

Mine was picked up by a small press for a limited print run, but the press shut down before the book came out. So it is possible, but usually under special circumstances. In this case, I had published a short story with that press beforehand and they just opened up to novellas and novels.