If you’re a Firefox user who has decried the lack of a feature akin to Safari’s Top Sites or Chrome’s Most Visited pages, you’re in luck with the release of Firefox 13 (think of it as version 4.9 in the real world). The update can now present you with a display of thumbnails of recently viewed and frequently visited Web pages, which can be pinned to a specific location within the display order, dragged to a different tile, or removed. You can also choose not to display the tab thumbnails by clicking the grid icon in the top right corner. Additionally, the Firefox default start page has been updated with a row of icons at the bottom that provide easier access to such browser
features as bookmarks, browsing and sync histories, and downloads, as well as the capability to restore the tabs from your previous browsing session. (Both of these features seem buggy, with at least some of us seeing only blank thumbnails and no bottom icons.) In addition to these user interface changes, Firefox 13 also adds several performance enhancements. When restoring a previous browsing session, tabs are loaded on demand instead of all at once, which should help to reduce memory usage. The release also supports the SPDY network protocol — Google’s alternative to the traditional HTTP protocol — which will be used by default by those sites that utilize it (such as Google’s search
engine and Twitter). (Free, 30.7 MB, release notes)
“tabs are loaded on demand instead of all at once, which should help to reduce memory usage” - this feature was already there in Fx12. I tried it, but considering that when I accessed a new tab, I have to wait until it loaded, I promptly went back to loading all tabs at once. In Fx13, they made it active again by default, can be checked off in the prefs as previously.