[snip] The problem is with the "World Community Grid Forum Signature Ranking" page, located at http://bit.ly/iECjqp - this is the page that suddenly becomes inaccessible. It appears to be affecting only some people and those only intermittently, but that is what these forums are all about, after all: Exchange information and see a bigger picture emerging.
I have the suspicion that the issue is related to the web servers at bit.ly, resp., net78.net, because it is occurring on weekends (at least for me). That may be a very premature conclusion, as I have openly admitted in my original email already, however, I believe it was fair to bring this up as a possibility. Perhaps others can successfully add to the pattern or clearly refute it. I am open either way.