Frankly the old version of the site sucked. I finally got around to launching the new version this past summer. I was hesitant to push it considering I had no real QA other then myself. It would have sucked to spent a ton of time/money to market it and then find a huge bug that drove all those users away.
Now that it's half way through the school year and there haven't been any issues I'm more confident. But it doesn't make sense to market it now, since teachers are already in their routine for the year. Next August I plan on making a bigger push.