My son loved this show as toddler. I have to admit that I loved it too. The very first time I saw it on Noggin, his dad and I looked at each other and busted out laughing. It seemed so absurd that something as simple as a fist with eyes stuck on could ever be entertaining to our son. But, seeing as our kid was easily entertained - he would easily spend 30- 40 minutes chasing a sheet of paper blown by a fan with absolute joy, I kept it on.
He would light up with a slight crease between his eyes in concentration. At this point, he was a little behind on his speech. He had speech patterns and the cadence down but wouldn't actually form words and we (read: I) were starting to worry.
Oobi, well mostly Ooma, gave him something to imitate. He didn't magically begin to talk but he mimiced the patterns and picked up words. I'd keep the show on even after he'd fall asleep because it was entertaining but also because I wanted to learn anything I could to encourage his communication skills.