I was one of the early, and daily, users of a small web app developed four years ago. Exactly one year ago, the app was acquired by a bigger company and shut down. It became now part of the services offered by the bigger company, if you want to use the service, you have to be a paying member of the bigger brand. I was thinking, why don't I go ahead and build something similar. I'm a software engineer and 1) will enjoy my time building the tool 2) others might pay for it 3) kind of long term, but if it's good enough it might be acquired as well. I'm not sure though if it makes any sense to build something that already existed before and was acquired by a big player. Curious to know what you think and if I should disregard the idea and focus on something else.
It's a great idea, especially if the bigger company has now made it bureaucratic, or complex, and users miss the days when it was a small, stand-alone site.
Also, since you were a passionate user, you probably know a few small ways to improve the site. Large companies that buy small businesses have a bad track record for continuing innovation of the acquired product.
Generally, you'll always have a better chance of success producing an App already in demand, independent of market share any company holds.
Consider the Apple II, Apple screwed over their customers and lost a suspected 80% market share + came very close to bankruptcy.
The IBM PC... well... IBM stopped manufacturing this hardware around 1982 after they went from 100% market share to around 18% + could no longer make a profit.
And my all time favorite Microsoft's destruction of the Skype product. They got so many complaints about Skype 8 that they locked the complaint thread after 48 hours.
Skype went from nearly 100% market share to spawning so many competitors Skype will likely go the way of the carburetor, buggy whip, 8 track cassette shortly.