But next-gen, recession-created squatters generally operate in reverse, flipping the legal concept of adverse possession. They tend to be homeowners who used to pay their mortgage, property tax and insurance, but then stopped paying the mortgage, either because their home is worth far less than they owe on it or because they are simply unable to make their payments due to, say, a job loss.

How many people are now squatting in homes they used to live in legally? It’s hard to say exactly, but the Mortgage Bankers Association reports that 5.4 million mortgages are presently delinquent or in some stage of foreclosure. And real estate data company Housing Predictor projects that 10 million foreclosures will take place between now and 2012. Some of these defaulting homeowners simply abandon their property. But the majority continue to live in the properties, payment-free, for many months, and even years, until they lose the legal right to reside there. Add to that the scores of tenants who (some would say justifiably) stop paying rent when they realize their rental property is in the foreclosure process. The bottom line is that the ranks of “squatters” today likely runs in the multiple millions.