On November 15, 2011, Mozilla announced, the Electrolysis project (e10s) will be placed on hold for the foreseeable future. What exactly is e10s? It is a lot of things that improve the performance, security and even stability of Firefox. The first part of e10s was back with Firefox 3.6.4 (May 2010) with Out Of Process Plugins (OOPP). OOPP introduced the plugin container, which allowed plugins such as Flash, QuickTime, etc to run in their own process away from that of Firefox. OOPP prevented a crashing plugin from taking the entire browser down with it. Also part of the current e10s is Places-optimization, and incremental garbage collection which came with Firefox 4.0 this past March.
However, two big features that would have come out the e10s would have been support for multi-core processors and multi-process architecture (like that of Google Chrome). The one feature I really like about Chrome is it already supports multi-process architecture. It is similar to OOPP, except that each tab runs as it’s own process. If you have ever looked at the Windows Task Manager with Chrome running you will notice there are multiple processes for Chrome, while there is only one main (and if applicable the plugin container) process for Firefox. The main advantage here is stability. Much like OOPP, one misbehaving website in it’s own tab won’t crash the entire browser. Instead, only that tab would ‘crash’ not affecting any of the other tabs.
Lawrence Mandel explains the reasons for the set backs,
Electrolysis is a huge undertaking. I can’t emphasize that point enough. Converting an established product, like Firefox, from a single- to multi-process architecture requires the involvement and coordination of many teams. Most recently I have been working with the accessibility, add-ons, front-end, graphics, and release engineering teams on various projects. Electrolysis requires a large investment of resources and time and has a long timeline for completion. How long? At this point we do not have a definitive answer as there are many unknowns that need to be investigated and addressed, such as how to ensure that add-ons can function in this new multi-process environment.
via mozilla links