I've been active on Wattpad for almost a year and on Tapas for almost two months. I've had a decent response to the short story and novella I've serialized on both platforms. At this time, the complete short story has a collective 3,800+ reads (it was featured on Tapas's front page as a staff pick). The ongoing/unfinished novella has a collective 1,200+ reads. These two accounts combined have 160+ subscribers with minimal crossover.
However, I'm hesitant to post content from either of my novels because I intend to seek traditional publishing for them. I've also seen others on the author forums for these platforms with the same hesitation, but nobody seems to have a definitive answer.
A. How much is too much to post?Does it matterIt doesn't matter
B. How/when should I tell an agent about my online author presence?In the query
1. How do agents and publishers feel about work that has been previously posted online? (if the work posted online is the same work being queried)It doesn't really matter
2. At what point does work posted online become notable/should be mentioned in a query? (if the work posted online is other than the work being queried)Always
C. Does it make a difference if you make money off content posted online?
Both Wattpad and Tapas offer "premium" stories, for which readers need to pay to unlock episodes/parts/chapters. None of my content is pay-to-read, but Tapas does offer ad revenue and a tipping system to authors over a certain subscriber count. So far I've received about $0.05 from ads and $6.22 in tips—does that make a difference?
D. Does it make a difference if content is part of the same series/IP?
The novella I'm serializing is a prequel to one of the novels I plan to query. Does this change whether I should mention it? Should I leave it out if the online response isn't impressive enough?No
There are more than a few authors who have transitioned to traditional publishing from these newish online publishing platforms. They generally had a Wattpad readership north of six figures.
It doesn't matter if your work has been on any of these sites. You just need to tell me about it in the query. The reason you need to tell me is that if we work together to sell your book, I have to tell the editor. And we must make sure any publishing contract reflects the fact that this work has been previously published.
Previously published is NOT a deal breaker; we just need to adjust the contract language.
Previously published can be a deal breaker for other things: contests are the first thing that come to mind. But again, if I know about it, I can manage it.
The biggest problem here is not that you're on Wattpad et al. It's that your readership numbers aren't high enough to be a selling point.