Hello Kps and thanks for your question.
RealtyTrac and other popular foreclosure listing sites only sort and provide information regarding public notices filed and made of record for a specific parcel or address. What you cannot know and will not know, of course, is if the home has been "redeemed" (meaning that the owner has paid for the past due portion on the mortgage) and/or if the owner has made arrangements with the lender(s) to sell the home short. Because an owner may redeem the home as late as just a few hours prior to the time when the home is scheduled to be sold at a Trustee's Sale on the courthouse steps, the 16 or 20 homes showing on RealtyTrac as "preforeclosure" or "auction" may never actually go to auction. If you really want an accurate feel for what will become an REO, you will need to go to the courthouse steps and wait for the sheriff's representative to announce which homes will or will not be sold on that day.
If a home is actually sold at auction--especially now, when the amount of the loans exceed the fair market value of the home--the successful bidder is usually the lender. Once the lender has title to the home (which can take a few weeks), the property can then be listed on the MLS for sale to buyers, like you! Homes purchased by a third party (and there are still third parties--bona fide buyers--who can pay all cash for a home) will often never be relisted for sale.
I hope this answers your questions. Good luck!!
Grace Morioka, SRES, e-Pro
Area Pro Realty