A quick heads-up, tonight, for a very thorough and interesting article on OpenCulture.org, about the available contents of Weird Tales magazine online.
Turns out you can download, or browse online, a number of issues of The Unique Magazine, for free.

And it is indeed an illuminating experience – if you like pulps, or supernatural fiction – because you can read the stories in their natural environment, together with the illustrations, the ads, the letters column etcetera.
Quite a different feeling compared to reading the same stories in an anthology.

The article also points to a number of other resources, and it is quite a find.