more and more people are realizing 10% interest a month on bitfinex will almost certainly make more than long term btc holding.
At 10%/month (what I've been making at finex), btc would have to be 6000 in 2 years.
I doubt most lenders lend out for months given the risk of goxings. Most are just lending out for a brief period.
I usually lend 66% of my money and use the remaining 33% for trading. Is a good balance, because the lends gives me a steady income (about 1.8%/week), while with the trading money I can have a good income from the market movements (like now... +30$ in 30 minutes).
Usually I lend money for 2 or 3 days, except when the offer goes over 0.4%, in this case I lend them for 30 days (but usually are closed earlier).
Nick.