The main friction IMO is exchanging fiat currency for btc. It's ridiculous. Sign up for gox, send a bunch of private identifying documents (to a site that's been hacked), send a wire transfer, wait a week... craziness.

I wanted to buy $10k of btc last week @ ~$100, I didn't have any open accounts anywhere, so I used coinbase... which limited the amount I could buy. I ended up with 0.2 BTC, which didn't post in my account until late last night.

Looking at today's quotes, it probably for the best.

For now. Once mining becomes slow enough (and it has to slow down over time), exchanges will have to charge transaction fees to make the "proof of work" worth their while.

You don't need to use an exchange to make a payment, though.

Its actually the miners who will be getting the transaction fees once the supply of bitcoins stops growing.