Interesting, I've never really thought about this "vanity argument" before, though I know that many programmers are reluctant to publish source code for the very same reason. Personally, I don't really care what it looks like, I just let whoever downloads it judge whether or not they find it useful.

I've also heard this argument, although I don't see the difference between releasing a PDF or the source file in this case. If the source code is not useful, because the document is of such low quality, then why would the PDF be?

Regarding the last point, I just put an \input after each problem. I have a separate folder from which everything gets included and a make-file that simply copies the actual solutions there or just an empty file depending on what flag I give "make". For people not familiar with build tools, there's the obvious solution of just maintaining two files, one with and another without solutions.

There's the large debate about open access journals and how much it costs the research community. On the other hand textbooks are also very expensive and controlled by often the same publishing companies. I've often wanted to write my own notes for a class, but not had the time. If I had someone else's notes to use as a basis, I would probably go with this option more often. I'm curious how many hours of work have been wasted reinventing the wheel by writing yet another set of linear algebra notes starting from scratch?

I was expecting one of these points to come up. Someone trying to make money is something that affects many open source software projects. There are websites trying to make money on packaging e.g. the 3D animation software Blender. Most open source projects just choose to ignore it, since it's very marginal and is hard to prevent. Not releasing their software as open source would, however, be a much larger net loss than making sure no one tries to make money unfairly on their work.

This is really the only forum I know where I could ask this, but I apologize if this doesn't belong here. There's another point I could also add to the list: if the students see the LaTeX code it might encourage some of them to learn LaTeX.