But still, you buy 1 btc with ~$97 at coinbase, and you can sell for ~$106 (easily) at localcoins. That's about 10% reward.
So if I got $700, I can buy 1btc each day at coinbase, and do that for a week. Then starting next week, the btcs will sequentially arrive. On each day I trade that coins immediately on localcoins, and immediately use that money to buy coins from coinbase again, and repeat this process. Then each week I will get about $70 back. And remember, you can always use the extra $70 and re-invest. So eventually your money will grow exponentially.
Somebody may argue that, money from localcoins may not be immediately usable to buy coins again. That might be true, like paypal for example. But I just need to prepare $1000 and extend my periodic trading to 10 days/period.
Isn't this too obvious? Any thoughts on that?
I noticed this also. I think Bitstamp and Coinbase both have much lower than Mt. Gox, and some of the buyers through Localbitcoins appear willing to buy at the Mt. Gox rate. I also noticed a few trying to sell BTC for 10% or more above Mt. Gox price.