This is because of Trulia's choice (similar to almost all non-MLS listing sites) to provide more market data to it's consumers, whether useful or not, is up to us!
Trulia will list homes as 'pre-foreclosures' or 'foreclosed' long before they are available for sale by the lender who has most often been the winning bidder at the Sheriff's Sale, because this information is public and they are compiling it for us. This information is used by Trulia to drum up interest in homes like the one you have posted the address to, as a foreclosed home, but the lender has yet to determine or process if/when the property will be brought to market to recoup any losses.
It is true that anyone may bid on a mortgage at a Sheriff's Sale, but at least around here it is uncommon for anyone beside the lending institution to bid on these properties, mainly due to redemption risk.
Larger lenders may have contracts with specific liquidators also referred to as asset managers to bring these homes to market via auction website.