The just-released beta 4 version of Firefox 3 shows a browser short on flash and long on important, useful improvements that make browsing the Web easier, faster, safer, and simpler to customize. The primary interface has been somewhat modified to look more modern, but much more important are a host of less immediately obvious features that any serious Web surfer will welcome.

Beta 4 offers a few visible additions to the browser. For example, the download manager has been improved, making it simpler to locate and work with downloaded files. It's quite nice -- you can easily search through your downloads. Also, Firefox now integrates directly with your virus scanner, and shows the scanning being done right inside the download manager. And you can see the icon of the file you've downloaded, making it a lot quicker to identify.

The zooming feature, already improved in previous betas, has been refined. You can now, if you wish, zoom in and out of the text (rather than the entire page); your settings are remembered, so you don't have to reset them each time.

In addition to visible features, there are a number of key changes to be found under the hood. Firefox has long been bedeviled by memory bloat problems, and with this version, Mozilla claims that it has gone a long way towards solving that. It claims that it has plugged hundreds of memory leaks. In addition, Mozilla says that it has cleaned up a related memory issue: that the browser uses increasing amounts of memory the longer it's in use. Mozilla says that Firefox now collects and releases unused memory, and reduces memory fragmentation.

Although I did not run specific tests, I can say the browser seems faster and does not slow down over time, as did previous versions. I tried the version for Vista; the version for XP shouldn't be much different.

Better browsing and bookmarking

Other changes to the browser have already been available in previous betas, but are worth mentioning. The most visible is the more modern-looking upper left corner with its icons for forward, back, reload, and stop. The forward and back buttons now have a 3D chiseled look, bringing what had been a tired-looking 2D interface into the modern age.

One not-so-nice change: Mozilla has moved the Home button off of the Navigation toolbar and onto the Bookmarks toolbar. This may have freed up some real estate on the Navigation toolbar, but it means that if you normally hide the Bookmarks toolbar (which I do), you no longer have access to your Home button. The change does not make much sense.

That being said, Firefox has done an exceptional job of turning the Navigation toolbar into a highly useful and powerful tool by integrating it with bookmarking and security features. For example, there is now a star icon on the far right side of the address bar; click it and you'll bookmark the site you're currently visiting. When you bookmark the site or visit a site you've already bookmarked, the star is gold; otherwise it is gray. To edit the bookmark -- for example, to change its folder, add tags, and so on -- click the star after it's turned gold.

Also useful is a new search-as-you-type feature. As you type an address into the Address Bar, a drop-down list of sites you've visited and in your bookmarks appears. The list includes not just the site URL, but also the site name and favicon .

Similarly, when you're visiting a site on which there is an RSS feed, an RSS icon should show up, as it did in the previous version of Firefox. (In this beta, I found that the icon did not always show up on pages with RSS feeds.)