When you use Slack, you don't "use it in a web browser", you use the (proprietary) software, delivered by Slack Technologies, which happens to run in a web browser. The fact that the web browser is itself free software is as irrelevant as the fact that the kernel and user-space services supporting skype on linux/bsd systems are open source. The actual software, everything that actually relates to the task at hand (group communication), is non-free.

Actually it's not completely irrelevant, as the fact that the host platform of proprietary software is free software has value in the security-based argument in favor of free software, but that's only tangential to the topic at hand.

Would it also be bad to host the project's source code on GitHub

Not necessarily, if really all you're using github for is hosting, then there's nothing wrong. That is, if you don't use their issues/PR system or other auxiliary services. This is how, for example, the linux project uses github. In this case, all that you're asking people to do is use git (free software) to download some stuff from servers owned by Github, Inc.

Running the website on IIS is fine though; this imposes absolutely nothing on your users or contributors.

But just visiting the project page on GitHub downloads and executes proprietary JavaScript. If that's a problem for Slack, why isn't it a problem for GitHub?

You don't have to visit Github's web ui at all if you're just using it as repository hosting. At least users and contributors don't have to, the maintainer needs to occaisionally for configuration reasons.

Also it's worth noting that github's entire UI, at least for browsing (I didn't try creating an issue or editing a file), works just fine with javascript disabled.

Don't all contributors have to at least set up an account through the web interface?

Even if you can connect to GitHub without ever touching their proprietary JS, that's clearly not the typical route. Just like you can connect to Slack using nothing but open source clients, but one is "enticed" to use the proprietary client.

> Don't all contributors have to at least set up an account through the web interface?

You can clone/pull anonymously from github and eg: email patches.

I'd say using github just for hosting read-only/read-mostly git is a bit like running http on IIS or email on Exchange - or indeed a propietary XMPP server that allows federation.

I'd prefer Free projects to use Free infrastructure - but building on established open protocols is good. Contrast with bitkeeper: you'd have to reverse engineer the protocol to pull/push - or with slack: there's no way to set up your own server snd federate with it.

Oh yeah, good point, projects can't bring their own user authentication system, so all your contributors have to have github accounts.

So OK, sure, github is as bad as slack.

Contributors won't be able to push to GitHub, but they can still push to a mirror repo or some other setup that then pushes to github.

GitHub's proprietary JavaScript is a problem, amongst others.

> Would it also be bad to host the project's source code on GitHub.

Some Free Software people certainly think that. It is imho at least problematic. For example, the unicorn web server developer, finds github problematic from the 'UX' side in addition to dependence on proprietary software and infrastructure (which creeps into the commit messages).

"Contributing to unicorn is socially as easy as contributing to git or the Linux kernel. There is no need to signup for anything, no need to ever touch a bloated web browser."[0]

[0]:http://bogomips.org/unicorn-public/20140801213202.GA2729%40d...

>The natural way to use Slack is to use it in a web browser, which could easily be an open source web browser.

The web browser may be free, but all of the JavaScript you are running is proprietary.

>And there are many closed-source IRC clients.

But there are many free ones, and there isn't an official client that is proprietary. It's possible to use Slack, more or less, over IRC or XMPP, but they are second-class citizens. The recommended way to use Slack is via their proprietary web interface.

I don't think I've seen anyone worried about running proprietary JavaScript in a browser before. I suppose that's consistent, but I don't know how many would agree with it. The utility of a web browser is deeply limited if you only use it to run open source code. As I already asked, do you also advocate against hosting the code on GitHub? That seems like the same problem.

The source of the JavaScript is open by virtue of being an interpreted language, and as such it can be edited and modified by the end user.

This is absolutely not true! The "source" is often minified JavaScript code, which is not the source code. In legal terms, it is a binary. It's a build artifact, the output of a program, not a human. Source code is the preferred form of modifying a program. The developers of a web application certainly don't use this form of their program when hacking on it. Giving someone a concatenated, minified version of a JavaScript web application is not giving them software freedom.

And even if the JavaScript files were not minified, they likely aren't available for user modification and redistribution because they are protected by copyright and a license that says "all rights reserved."