And yes, you really can do business presentations. True, quality is no match for a $500 projector 10 times its size, and 6 times its weight, but that's the point. Need to present to people in their offices, or in front of just a few people where a 3 or 4 (or even 5) foot screen size is fine, the PK320 will do the trick handily!
If you get the XP8000 or a different external battery pack (there are plenty thanks to iPad, iPod demand for spare batteries) It would seem a charger that can recharge an iPad once, if compatible should be able to power a PK320 for perhaps 2+ hours of viewing!
One major market I've mentioned for this projector would be missionaries and field volunteers of all types- call it worship industry. In my dealer day years ago, we sold hundreds and hundreds of an old "pocket" projector called the PK20 - a Mitsubishi with 50 lumens (far larger projector) to large church organizations to provide to their missionaries and other folks helping out around the world. That PK20 was a huge success, but then those pocket projectors of the day, got brighter, and no more battery capability.
This is a Pico projector! It lacks plenty of features of larger projectors. Even when it has some features it may not be the same thing. For example, it has a speaker (tiny but rated 1watt), but that's not exactly big sound. My MacBook Pro is effectively just as good, and almost any larger projector will do much better than the Mac. The sound from the PK320 isn't what I have in mind when watching a music video. Still, I appreciate that it has an audio out, so grab a good, very small, portable powered speaker, and you can do some real audio.
Picture quality is fine for most things. It's not highly accurate, but very usable for personal videos and photos, more than adequate for a real presentation before a couple or three people for business.
Improving features, jumping to 2 Gig, Office document support, pdf, jpg, various video formats and more, the PK320 has few sources and content it can't project, up to its maximum resolution.
Of course there are plenty of other uses, for fun and business.
There are smaller picos, there are laser picos, there are the 2 - 4 pound pocket projectors, that are not 200 to 500 lumens. Plenty for you to choose between.
However, if 100 lumens and battery capability will do good things for you, I can't think of a better thought out, or functional tiny projector.
And for that - our Hot Product award - one I personally think is particularly well deserved.