Those are good ideas for showing inactive links, but the simplest approach (I suppose) would be to replace the period with something like a double asterisk ** (the doublet being more visible than a single asterisk, easy to type, distinct from any URL content, and easy to target for replacement by visitors who want to check the original site). e.g. researchcooperative**org
On the other hand, having URLs visible at all is kind of ugly, and for aesthetic and readability reasons, there is value in showing a journal title and embedding the link in the title. I doubt that a single blog will add greatly to the SEO of a particular journal.
For visitors here, it is convenient to be able to click through to the journals under discussion.
Cheers, P.