In 2009, with a friend, I launched gdocsopen.com, a way to use google docs for local office documents. After launch, we got some really good press.
Fast forward 3 years, after which I put some effort into the website & app, it's not working really well (2-3 sales / month). I realised that the market is really small.
What do you advise me to do? Move on or keep trying to succeed with this app?
I realize I'm restating what other people said, but with many things, I think the math speaks for itself, or at least, it should. Run the numbers as ruthlessly and exactly as you can. Then make your decision based on that.
If your heart is in this, maybe you can adapt it somehow so that the numbers are more promising. But let the numbers speak.
If you were doing a lot of sales when you were getting good press you clearly have an application that people want and are willing to pay for. In that case you might be able to substantially increase sales by spending more time on marketing.
If you do decide to move on to something else, maybe you could offer the app for free and encourage social sharing both in the app and on the website. You could then move back to the project if downloads pick up as a result.
Maybe you can also support office365, zoho, and any other web based alternative to some locally installed piece of software. That would potentially allow you to pull affiliate fees for driving new customers to software you support and/or get some promotion or marketing from those companies.
The other issue is that Microsoft now uses "the cloud" to store all your data, treating your computer as a terminal, therefore people have no need for your service!
that's exactly what my app does: it uses the cloud to keep any documents you open :)