I do plan to have an option where users can read past editions on the site. I consider the Newsletter an unfinished feature because it does not yet have this. My plan is to show the archives as html though not PDF. I do not know of any free or commercial software that can convert html to pdf and make it look as it should in a browser. I do beleive there are some free libraries that can be used to produce pdf files from text content but I don't know about converting it with style and markup. I also do not know how soon I will get to implementing the archive feature, but it is on my list.