Anecdotally, webOS devs, given the low threshold of competition and influx of new Touchpad owners, are doing pretty fantastic sales right now. Good for a quick return at least. Since HP's also being charitable and giving away 6-packs of apps for free (and paying the dev for each one at full regular 70% share), a couple of those devs picked found themselves 5-figures richer overnight. No idea how long they intend to keep doing it, but it seems ongoing for now.

Good platform for quick wins. Mid-term and longer, it'll largely depend on whether webOS finds new hardware with which to keep it alive.