Multi-process browsing is quite handy; it is already enabled in Google's Chrome browser and Microsoft's Internet Explorer 8, and it means that each page runs in a separate process which leads to added security and stability, because if one page goes bad, it doesn't affect the others. This new feature is now coming to Firefox users in the future, through a project Mozilla is calling Electrolysis, according to Ars Technica.
A prototype has already been assembled featuring said project, and a list of Mozilla's benefits can be found below, taken from this blog post:
Mozilla had explored the possibilities of this in the past, tossing ideas around the developer community, but apparently it didn't go anywhere until Microsoft and Google implemented it into their respective browsers. However, it won't be an easy task at all to get Firefox working this way. Here's the current plan on what to do to tackle it, taken again from the previously linked blog post:
A screencast has been posted by Firefox developer Chris Jones, which you can download here in the .ogg format. It shows the functioning prototype of the browser, and demonstrates that when a page crashes, only the content disappears and the user interface remains just swell. He said, "Notice that only the 'content' disappears when the page crashes; the user interface itself keeps running as if nothing happened. This is a big step forward. With Firefox protected from buggy pages and plugins, more fun is possible. This video shows me pressing a 'Recover' button that relaunches the page that just crashed. There are many more possibilities for recovering from these errors, and I'm excited to see what our user interface folks cook up."
Please note that the team is currently working on Windows and Linux versions of this new feature initially, as apparently they are more comfortable in those environments, and a Mac version will come later once they work around difficulties. Be sure to keep an eye on this, Firefox users, because it will certainly improve your browsing experience.