I am relatively new to Ninjatrader and to day trading. I am, however, VERY experienced at developing software. I have written a couple of indicators and found the process fairly straightforward. Is there a market for these things? Is it worth my time to get serious about building indicators and strategies for others? Basically, if you can explain it to me, I can write it. I just don't know if people can, will or do pay for these things. I'd love to hear from other developers on the subject.

No.
People who wants to have something coded are in most cases not very technical andcan't easily describe what they want in a logical way. It's usually 10 times longer to understand what they want, and eventually answer something like "No, it's not possible to do this.", than code it.
If prospects were really aware of what they want and able to organize it in their mind to simply code it, then it would be an easy business, but the reality is very different.

Hi,
Thanks for the response. Figuring out what users really want is what us developers really get paid for. Writing code is easy!
Thanks again ... Ed