Why Zillow, Redfin & Realtor.com Show Different Histories for the Same Property (And What Boston Buyers Must Know)

Zillow, Redfin, and Realtor.com display different listing histories for the same property due to fundamental business model differences: Zillow (media aggregator) anchors to parcel IDs and stitches history algorithmically; Redfin (brokerage) follows strict MLS display rules that honor listing ID resets; Realtor.com (NAR partner) prioritizes agent-friendly presentation. Days on Market resets via delist/relist cycles using 30/60/90-day MLS windows, and buyers who cross-check platforms gain critical negotiating leverage by uncovering hidden market exposure.