We all fall victim to the dangerous belief that if an app or extension is listed in an official repository - be it the App Store, Google Play, the Microsoft Store, Mozilla's Add-Ons directory or so on - it must be legitimate. After all, the big tech companies surely use a lot of automated systems (and real human beings) to ensure that their customers aren't downloading harmful things. Right?

Suppose you're trying to troubleshoot a family member's computer, you want to show a friend some issue you're having with your system, or you want to make a quick recording of some crazy thing you're about to do in a game. With the Chrome extension Loom, it's incredibly easy to capture and share a quick recording of your screen right from of your browser.

Firefox's design hot-shot Aza Raskin is back with some more interesting Firefox prototyping, this time in the form of a fresh idea for the new tab page. The page borrows some thoughts from Google Chrome and now Safari's default new tab pages (i.e., displays thumbs of pages you like to visit and offers a search box), but puts a slightly different spin on it. Most notably, for sites like Lifehacker, the new page appears to tap the site's RSS feed to display the most recent posts. We've been playing around with it a little bit this afternoon, and though we're excited to see where it'll go, so far it's pretty rough around the edges—both in form and function. If you'd like to try it out or you want to know more about what the designers were thinking, hit the link.

Firefox with the Greasemonkey extension: You're cruising through your unread items in Google Reader, and suddenly you want to mark all the items AFTER your current one as read, or BEFORE your current one as read—but not all of them. The Mark Until Current As Read Greasemonkey user script can do just that. With it installed, press Ctrl+Y to mark items before the one you're looking at as read, and Ctrl+I to mark items after as read—a nice feature for power GReader users. The Mark Until Current As Read user script is a free download, works with Firefox and the Greasemonkey extension, and is currently on deck to be included in the Better GReader extension. Thanks, CliffordBadger! Google Reader - Mark Until Current As Read v 1.2

Firefox only (Windows/Mac/Linux): Firefox extension Panic provides a simple keyboard shortcut to instantly close all of your current tabs while opening a new, more appropriate one. So let's say you're at a workplace that supports reading Lifehacker (you are boosting your productivity, after all). You could set Lifehacker as your panic URL, then start looking for your boss's birthday present on Amazon. (You are so nice!) When your boss turns the corner, just hit the customisable keyboard shortcut to close your active windows and fire up your panic URL. Of course, Panic's boss key would work just as well for less noble purposes, and it works fast. Panic is free, works wherever Firefox does. For other Panic alternatives, check out previously mentioned apps like the Magic Boss Key, Windows Hidie, and workFriendly. Panic

Firefox only: Save time shopping at Amazon.com with the new Better Amazon Firefox extension, which adds helpful tweaks and features to Amazon's pages. Better Amazon highlights which products the big A offers Super Saver free shipping for in search results, automatically enlarges product images, shortens Amazon URLs for easy emailing, and collapses superfluous junk on the page when you just need to get simple tasks done. After the jump, download Better Amazon and get your (stateside) online shopping done more efficiently.

Just posted an update to the Better Gmail 2 Firefox Extension which updates the gorgeous Redesigned skin to its latest and greatest version. Download version 0.5.1 here.

Firefox only (Windows/Mac/Linux): The CyberSearch Firefox extension transforms Firefox 3's AwesomeBar into a dynamic search box capable of returning results from popular sites like Wikipedia, Google, and more. The extension is fully customisable, so you can define keyword shortcuts for just about any search you can think of. For example, you could create a Lifehacker-only Google site search so that typing something like lh gmail in your AwesomeBar would give you the first page of Google results directly in the AwesomeBar. Choosing a result will take you directly that page. Luckily you don't have to create the Lifehacker-only search if you don't want to, as the extension already includes a custom search using the keyword techy that searches only Lifehacker, CyberNet, and Download Squad. Hit the jump for a video of CyberSearch in action.

Windows/Mac/Linux (Firefox): Site-finding service StumbleUpon has taken full advantage of Firefox 3's "Awesome Bar" by integrating its browser toolbar/extension with Firefox favourites. A new option in the latest version of the previously highlighted StumbleUpon add-on lets you download all the sites you've rated with a thumbs up/"I like it!" into your bookmarks, giving you as-you-type access to that last cool link you saw but can't quite remember. Your recent favourites and their tags are also stored in the browser's "Recent Bookmarks" and "Recent Tags" Smart Folders, helping your organize your idle-time browsing. StumbleUpon 3.23 is a free download, works wherever Firefox 3 does. StumbleUpon 3.23

Windows/Mac/Linux (Firefox): Free review-aggregating extension Pluribo adds a subtle tweak to Amazon product pages that can often have hundreds, even thousands of reviewers weighing in on a product. After scanning the reviews, Pluribo adds a small pop-up bar at the bottom of each Amazon page, stringing together the most prevalent adjectives and thoughts on each product into one or two cohesive lines. Hovering over each adjective gives you a pop-up with more detail on how it was used, so you be sure you're avoiding the same kind of editing used in summer movie posters. The extension works mostly with electronics at the moment, but the creators aim to expand soon. Pluribo is a free download, works wherever Firefox does.

Pluribo

Windows/Mac/Linux (Firefox): Open It Online, a free Firefox extension, cuts out all the middle steps between finding a document in a Google search, in your web mail, or anywhere else online, and getting it open in a web-based office/editing suite. In other words, it adds an option to your Firefox "Open With" dialog to let you open Word documents, spreadsheets, PDFs, and more file types in Google Docs, the Zoho suite, ThinkFree Viewer, and other locations. You can pre-set defaults for every file type, and that's just about it—nice and convenient for fans of online editing. Open It Online is a free download, works wherever Firefox 2 or 3 does.

Open It Online

Mac OS X only: Firefox extension Quartz PDF enables inline viewing of PDFs in Firefox 3 for the Mac. Just install, and next time you follow a link to a PDF, it quickly loads the PDF directly inline. Quartz PDF is lightning fast, and works exactly like you're viewing the PDF in Preview. It'd be great to see the thumbnail navigation sidebar in a future release, but as is this extension works like a charm. Quartz PDF is free, requires Firefox 3 and OS X 10.4 or higher. Quartz PDF