I've been doing some research on online magazines, and I've found two things particularly frustrating:
First, a great many web pages do not have publication dates on them. If you're publishing anything online, but especially a magazine, please consider putting a publication date on every story, or at least on every issue. You'll make things easier for a lot of people: readers who want to nominate your material for awards, journalists and academics and history aficionados who are doing research; bibliographers; readers who arrive at a given page via a web search rather than by navigating your site; etc.
Second, a lot of magazines have About pages that say what the magazine's focus is (that's great!) but don't say anything about its history. This is something that's of interest to a much narrower audience than the date thing above; still, for a lot of online publications it's remarkably difficult to find out simple facts like when the magazine launched. Consider adding a little bit of info to your About page (or maybe to a separate History page?) that gives some background on who founded the magazine, and when, and why, and whether you've undergone any major changes in policy or approach or guidelines or pay rates.
Stuff on the web can sometimes last a long time, but other times it can be really ephemeral; for example, if you take down your archives after a couple of months, then figuring out stuff like how long you've been around and who you've published can be difficult. And more generally, trying to trace the history of an online publication, especially one that's ceased publishing, can be pretty hard. So the general point of this entry is: think about documenting your publication for people who might want to know more about it in the future.