Posting master's thesis on arxiv? I read this question, in which all answers recommend posting one's master's thesis online. My thesis is available from my university's repository, but I'm thinking about posting it on arXiv since it's more easily searchable. However, I don't think I've seen master theses on arXiv. Is this something that people typically do? Are there disadvantages that I'm missing?
Posting a master's thesis on the arXiv is uncommon, but not unheard of.  My feeling is that there's little point to it: if there's material worth publishing in your thesis, then you should turn it into papers and post them on the arXiv (in which case the thesis is unnecessary), and if it's not worth publishing then it's not worth posting to the arXiv.

If you decide to post both the thesis and the papers to the arXiv, you should indicate the relationship between them clearly in the comments so you don't look like you are inflating your publication record with duplicates, as well as in case you trigger the automated plagiarism detection in the arXiv.

One potential issue is coauthors.  If anything in your thesis is coauthored with someone else (either from a previous paper or to appear in a future paper), then I do not think you should post the thesis to the arXiv.  The problem is that you'd be pointing readers towards a version that lists you as the only author and relegates your coauthors to a brief note in the text, and you would be increasing the chances that they would cite the thesis rather than the coauthored papers.  Instead, it's best to emphasize the papers by posting them to the arXiv instead.