The latest version of Firefox, Firefox 26, is now officially available to download. This is one of the most significant releases in recent history, introducing built-in "click to play" functionality for all plug-ins (except for Flash). Firefox 26 also represents the dramatic culmination of Mozilla's MemShrink project, which has spent the last two and a half years trying to battle Firefox's reputation for being a memory hog. Firefox 26 has a very svelte memory footprint indeed.