Somehow, I think Doug said it best:

Avoid, also, straw style filters through which you literally suck the water. Though the concept is appealing, especially for weight conscious survival use, they don't filter very well in the first place and clog very quickly and are then useless. In fact, the EPA forced them off the market a while back, but you still see them around, or you may even have one, in which case, you ought to ditch it.

Also, in response to something on that site:
Quote:
At about an ounce in weight, this survival water filter straw takes out giardia. It will also make you the star of the backpacking trip with friends and colleagues.

So, you become the "star" of the trip because you can remove giardia lamblia cysts from your water? Why? Does no one else on your trip have a water purification system? If so, you need better friends and colleagues to go backpacking with. Add to the irony all of the stuff you'll catch since you're all sucking on the same straw, but at least the giardia lamblia cysts are filtered! <img src="/images/graemlins/tongue.gif" alt="" />
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“Hiking is just walking where it’s okay to pee. Sometimes old people hike by mistake.” — Demitri Martin