Merging a branch (usually a feature -> master) using the "no fast-forward" (ensuring a merge commit) and the shortcut for the "previously active branch". git merge --no-ff -

Activity Streams are definitely ubiquitous these days! The article has some great examples of open-source packages though I would add the Stream hosted service and the related open-source stream-framework.

Price at whatever the market will bare. If you have other altruistic or charitable reasons, go ahead and charge less. The question also suggests that your users are making money via your app (as a platform or marketplace). AirBnB take ~15% and most advice I've heard from around the startup industry is that 10-20% is standard.

This post has some helpful suggestions: https://medium.com/@alexmngn/how-to-better-organize-your-react-applications-2fd3ea1920f1

I'd vote for splitting into two files earlier as it will likely end up being more manageable in the long run. If you're looking to distribute via a package index (unlikely) there maybe be some benefit to keeping a monolithic manifest. Although it's mostly just a matter of personal preference.

I'm always scratching down notes. It's probably different for everybody but it definitely seems to help me process problems and to remember things later on (which in a sense is self-defeating but it turns out to be a positive hack).

There's no technical reason why you can't use a combination of jQuery and React. Though for most greenfield applications it would be advisable to pick or the other, depending on the current needs and future goals of the project. There are a couple ways to facilitate interactions between components in React. In simple cases you can push 'props' and event handler functions downward from a shared root component into the relevant child components. For more complex applications it can be simpler to facilitate access to shared state (Redux is a popular library that provides this functionality).