Debt has a bad name, for good reason - too much of it helped sink the economy in the Great Recession. But there's a good side to debt, too, and here are some sites to explain it.
Good debt, bad debt. The Money 101 lessons at CNNMoney give examples of good and bad debt. In general, it says, "Good debt includes anything you need but can't afford to pay for up front without wiping out cash reserves or liquidating all your investments. In cases where debt makes sense, only take loans for which you can afford the monthly payments."
Credit utilization. Your debt-to-credit ratio, or credit utilization, tells how much you have actually borrowed of the total credit available to you. As explained here at About.com, if you got a $1,000 credit limit on your card, and your balance is $300, your credit utilization is 30 percent. The lower that percentage, the better for your credit rating. In that regard, more credit is good - until you slip into actually using too much of it.