It's a mild stimulant and intoxicant when chewed and on some islands it's the center of social life.
On other islands it's frowned upon because betelnut is highly addictive, discolors the teeth, is the source of a gross byproduct, is associated with mouth cancer, and some experts say it slows the mind.
Many of our students at PIBC arrive on Guam with well-developed betelnut habits -- habits with which they constantly struggle. (Betelnut is prohibited on campus. But students can chew off campus if they choose.)
The people at BoingBoing have over the years been strangely infatuated with the whole betelnut thing.
The video clip below focuses on the betelnut retailing industry in Taiwan. They rely on another stimulant to enhance sales.