Thanks for this feedback Reziac. A just-sorted-by-date section does make some sense, I will ponder what is feasible here in terms of navigation (one prototype of the site had a specially colored "Misc." section but I was not yet completely happy with it). Pls note you can already search by year (e.g. [1923], or in combo with a keyword) and you can search by decade by entering e.g. [1920s] or [1930s], and then page through the first 1,000 results.
And you're right, sources are included independent of whether an ad can be bought from there (and if there's a buy link there, it will be independent of whether or not I have an affiliate account with the site... I consider it useful). This is a museum and gallery site that's meant to be enjoyed by people and to be useful, and everything else is secondary to that goal. As you might expect I will run into problems if server costs are making me bankrupt, but other than that, I'm happy if I just cover server costs (if more, I'm very happy too of course, but not in a way that clutters the site or anything).