ETFA Discussion and Fanartery

From my limited observations, building an audience for a forum adventure is generally easier if you've got the following. You don't need any of these to gain a readership but they certainly help:

-Solid art (not always an option, not necessarily a factor if you update consistently/make really good words)
-A really engaging opening (not always an option if your narrative preference is to ease into the action. Can be mitigated by soliciting character/worldbuilding suggestions, but that can go too far in the opposite direction and make your setting feel generic without reader input).
-Thread visibility. The more time you spend on the front page, the better the odds someone who's just browsing is going to click on your thread. Other than updating really consistently there's not much you can do about this; threads seem to drop off the front page in two days currently and that time'll only shrink if the forum grows and more threads are "competing" for that sweet forumnular real estate.
-Nepotism. I have on at least one occasion nagged a friend to give me a workable suggestion for an adventure.

It really depends on how you like telling stories! If you rely on reader suggestions as a springboard for writing updates, then you might be in a tight spot, as threads probably won't get further suggestions once they fall off the front page.

tl;dr "it's totally up to you, but if you're going to rely on suggestions, better make it once every couple of days"