When is debt, not really debt?

When is debt, not really debt?  When other people pay for it... voluntarily. 
That's the case I'm in right now.  A few months ago, I was in a quandary.  Our family was moving out of state and we wanted to sell our house.  Unfortunately, we could not find any buyers willing to pay the amount of money equivalent to our outstanding mortgage.  We couldn't even find buyers willing to pay $20,000 less than the amount of our outstanding mortgage.  Our choices were getting slim until we realized that with that debt, came an asset.  An asset we could leverage to pay off that debt.  So we did a simple thing, we found someone else to pay off our debt in exchange for their use of our asset (commonly called renting).  Of course we are dependent on a few things for this gamble to succeed. First, we needed to find and keep good renters.  Given the number of foreclosures in southeast Michigan, there are many families who do not have the credit to buy a home in the near future.  Our first tenants seemed ideal. An established middle-aged couple, one of whom is an executive in a small company, the other of which loves yard work.  They decided to walk away from a $400,000 mortgage and rent for a few years.  With a two year lease, we should have some stability in payments and they will have a home they can afford and enjoy.  Win-win!
The second thing we were counting on is that the housing market in our area would turn around, or at least stabilize from the plummet it was in for the past 5 years.  There was evidence back in June that Michigan had started a significant recovery and that evidence is looking stronger today.  As Bloomberg states:  "Michigan’s economy is recovering from the recession at the second-fastest pace in the U.S..."  They further state: "Mortgage delinquencies dropped at the fourth-fastest pace in the U.S., and personal income and employment growth ranked in the top third, according to data compiled by Bloomberg."  Granted, Michgian was at the bottom in terms of impact of the recession, but its recovery is solid and (hopefully) lasting.  With more jobs comes greater demand for housing and hopefully increasing prices. 
Even if the housing prices do not bounce back, the rent from our tenants will pay off the principle on our mortgage, so that in 5 or 10 years, the principle will decrease to a point where paying off the loan will not put us in the red.  If the housing market does bounce back, we may be fortunate enough to walk away with some capital to invest in larger cash flow investments.
So while we do have significant debt, it is not debt that negatively impacts our personal financial picture.  As Robert Kiyosaki, of Rich Dad, Poor Dad fame, would say, this is how the rich get rich.  The rich have other people pay for their debt, but they do so in a mutually beneficial relationship leveraging their assets where everybody wins.