Hey guys, I just picked up and read through my copy of the aforementioned book and in the final story (minor spoilers to follow), there is a very conspicuously placed link in between panels, with a background of puzzle pieces, Riddler's trademark. Since the story is his and all about how he's really much smarter than most give him credit for, I thought maybe this might lead somewhere (or perhaps I simply got a misprint). The link reads thusly:
http://bit.ly/_ _ _YHP_
I tried flipping back through the issue for clues, but all I found were a series of oddly bolded "k"s and "s"s where they ought not be... seemed like it could be significant, but it amounted to gibberish. Here's a pic of the link, as well as a similarly conspicuous grouping of symbols that appeared to be completely unrelated to the story on the next page.