http://money.cnn.com/2012/08/09/technology/knight-expensive-... https://www.sec.gov/litigation/admin/2013/34-70694.pdf?page=...
Google : Social & Chat applications.
Google+, Hangouts, Allo, Duo
Other than core products, Google made lot of mistakes(both engineering & non-technical) in all the products.
Google actually helped me to understand this important point: You and I will never ever create another Facebook. Sure, we can create smaller community-like platforms, but there is no reason for us to believe that we can be greater and better than Facebook. And we don't have to be. There is no sense in pretending. There's not even a sense in trying. Therefore, find smaller projects to work on, and specialize in them. There are a great many things that Facebook cannot and should not do. There are a many great things that you and I cannot and should not do. But then, there are also a great many things that we can do!
Before this, I used to get upset and it probably prevented me from even wanting to start projects or come up with ideas. I was always thinking big: "How do I create something like the next Facebook." Once I set this mindset aside and focused on the smaller picture of just developing useful apps, and getting them out into the world, it made things better.
I had finally realized I was completely focused on the wrong thing. There are many things that Facebook is not good at and there are things Facebook is good at. There are many things Facebook cannot do simply because they are not in the business to do it. There are things that Facebook also implemented into their platform that just doesn't get as much use or attention as it should. Those little flaws in the system are the things the "little developers" can take over and specialize in.
I created https://mypost.io which is an easy-to-use platform that lets you put up a webpage on the Internet in seconds. I posted it on Hacker News (https://news.ycombinator.com/item?id=10552168) and it got absolutely no attention at all. And other than telling Twitter and a few Facebook friends about it, it has had no advertising or media attention. Yet somehow, the entire world is using it. By "the entire world", I mean people from around the world. Not thousands of people, but a few hundred at least. I've seen people from Russia, Brazil, Australia, Germany, and Japan using it. How did it get around the world within a year? To date, there have been over 2,500 posts created. Might not sound like a lot, but I'm not Facebook and I didn't spend any money advertising it. I could have spent more money and time advertising it, but it was just a fun platform that helped me understand what people like and whether my applications were useful or not. I mean, I really just created it for myself, as I do all my web apps. I simply share it with others and if they enjoy using it and find a use for it as well, than that is a success to me.
Lesson learned: Stop developing apps for other people. Develop them for yourself and make it user-friendly in the process. If you find it useful, it is more than likely that others will find it useful as well. Either keep it free or figure out how to monetize it and make a little money for your efforts. That is what I am in the process of testing and learning now: How much will people pay for something they find useful?