I continue to notice an unsettling trend: the rise of the GitHub monoculture. More and more, people seem to believe that GitHub is the center of the programming universe.
Don't get me wrong, I love GitHub. It succeeded at capturing and promoting the social aspect of development better than any other site. And git, despite its flaws, is a great version control system.
And just to be clear, I am not talking about the recent turmoil about GitHub's internal culture. That's a problem, but not the one I'm talking about.
Someone said to me, "I couldn't find coverage.py on GitHub." Right, because it's hosted on Bitbucket. When a developer thinks, "I want to find the source for package XYZ," why do they go to the GitHub search bar instead of Google? Do people really so believe that GitHub is the only place for code that it has supplanted Google as the way to find things?
(Yes, Google has a monopoly on search. But searching with Google today does not lock me in to continuing to search with Google tomorrow. When a new search engine appears, I can switch with no downside whatsoever.)
Another example: I'm contributing a chapter to the 500 lines book (irony: the link is to GitHub). Here in the README, to summarize authors, we are asked to provide a GitHub username and a Twitter handle. I suggested that a homepage URL is a more powerful and flexible way for authors to invite the curious to learn more about them. This suggestion was readily adopted (in a pending pull request), but the fact that the first thing to mind was GitHub+Twitter is another sign of people's mindset that these sites are the only places, not just some places.
Don't get me started on the irony of shops whose workflow is interrupted when GitHub is down. Git is a distributed version control system, right?
Some people go so far as to say, as Brandon Weiss has, GitHub is your resume. I would hope they do not mean it literally, but instead as a shorthand for, "your public code will be more useful to potential employers than your list of previous jobs." But reading Brandon's post, he means it literally, going so far as to recommend that you carefully garden your public repos to be sure that only the best work is visible. So much for collaboration.
There is power in everyone using the same tools. GitHub succeeds because it makes it simple for code to flow from developer to developer, and for people to find each other and work together. Still, other tools do some things better. Gerrit is a better code review workflow. Mercurial is easier for people to get started with.
GitHub has done a good job providing an API that makes it possible for other tools to integrate with them. But if Travis only works with GitHub, that just reinforces the monoculture. Eventually someone will have a better idea than GitHub, or even git. But the more everyone believes that GitHub is the only game in town, the higher the barrier will be to adopting the next great idea.
I love git and GitHub, but they should be a choice, not the only choice.