Putting Semiformal "Nonpublications" on your website
I see very little danger in putting those documents onto your website, and indeed I encourage my students to upload everything they produce and that may be of any value. My line of thinking is that we are after all paid by taxpayer money, so it seems only fair to make as much of what we do available in some way if possible.

Of course, the elephant in the room is how those "others interested in this work" will actually find your notes if you just upload them to your website as PDFs ...


  What would the cons/risks be?
  So far my main concern that I have thought is that it might make me look bad by making available, less than perfect work. Some of these may lack suitable referencing for example.


I do not think that there is a real danger in "looking bad" as long as it is clear that whatever you upload there is just quick, informal work (and, of course, as long as the work does not contain, e.g., hate speech, but I guess this goes without saying). Lacking suitable referencing may be a more real problem, and I would likely put in the few extra minutes to add appropriate attributions for every text that I put online somewhere. However, even if you decide not to do this, it is very unlikely that somebody down the road would get agitated over not being properly cited in a document called "Some Informal Notes on [A]". The key here is that you make clear that this is not a preprint of a paper or even a technical report in the traditional sense, but "only" an informal note. Hence, it should be clear that the content isn't meant as a scientific publication. This should alleviate most concerns that you are passing off other's work as your own.