Property tax is subtle, but here's what it looks like in a nutshell:
The article talks about treating it as property vs currency. If the IRS chose currency, all realized[1] gains/losses on BTC get treated as ordinary income (lumped in with salary/wages) and get taxed at income rates. For most bitcoiners this would be around 15% if your salary is under $75,000/yr[2] and around 30% if more.
If the IRS chose property your tax rate depends on how long you held it (and some other things, it's subtle. But mostly how long you held it). If you bought and sold within a year it gets pushed into ordinary income as shown above. If you held it for over a year you pay 15%[3] on the gain.
Note that property transactions still kick into gear even if you didn't cash out into dollars. If you bought in at $10/BTC, get a new lambo[4] at $1000/BTC you pay the property tax (capital gains) on the bitcoin gain.
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[1] Gains from when you cash out (cash out price - buy in price)
[2] Upper middle class in most of the country, excepting the very big and trendy urban centers
[3] If you sold those collectible bit coins you'd probably pay 28% on the gain.
[4] So there's this guy, and he's got a brand new Lamborghini and he wants to put a mezuzah in it...