The feature, dubbed "Places," was to be a rewrite of Firefox's bookmarking system, and would have allowed users to search through both bookmarks and the browsing history log to locate sites. Places relies on SQLite, an open-source database engine, to store bookmarks and the history data.
"As we have been preparing for the FF2 [Firefox 2.0] Alpha2 on May 9 it has become increasingly clear that we do not have time to complete an implementation of Places that lives up to our standards," wrote Mike Schroepfer, Mozilla's director of engineering, in a message on a developer's message forum.
"Rather than rush it to market, we'd prefer to spend the time it takes to get it right," Schroepfer added.
Places has had a rocky history. For a time it was pulled from development of Firefox 2.0 Alpha 1 -- also known by the codename "Bon Echo" -- because it wasn't up to snuff. However, before Bon Echo launched last month, Places was put back in.
"This is a difficult decision," admitted Schroepfer. "But doing it this early in the release cycle gives us the time to focus on delivering an extremely high quality FF2 in Q3 and gives Places the room it needs to develop into a truly innovative feature."
Although Places was considered by many to be the biggest addition to Firefox 2.0, Schroepfer touted the update's remaining improvements, including better security and tabbed browsing, and faster performance.
Others, responding to Schroepfer's announcement on the same message thread, voiced more disappointment.
"Without Places, Firefox 2.0 will have nothing new," wrote Matt Nordhoff. "From your post, Firefox 2.0 sounds like it should be called Firefox 1.6."
Users of Alpha 1, which had Places enabled, will be able to export their existing bookmarks using a new feature to appear in Alpha 2 when it releases May 9.
Mozilla isn't the only developer to scale back expectations. Microsoft's history of backing away from major features in Windows Vista -- including a new advanced file system -- has been well-documented.