dabblet is an interactive playground for quickly testing snippets of CSS and HTML code. It uses -prefix-free, so that you won't have to add any prefixes in your CSS code. You can save your work in Github gists, embed it in other websites and share it with others. Follow @dabblet on twitter

It currently only supports modern versions of Chrome, Safari and Firefox but I'm hoping to expand browser support soon.

It’s handcoded by Lea Verou with care but some other nice folks helped too.

Everybody loves the drag and drop nature of OS X. Drag an app into your applications folder, and it's installed. You'd think it would be that easy to delete an app — just a matter of dragging it to the trash. But it's not. Apps install support files on your computer that generate clutter. Introducing AppZapper. Simply drag one or more apps onto AppZapper. Then, watch as it finds the extra files and lets you delete them with one click.

AppleJack is a user friendly troubleshooting assistant for Mac OS X. With AppleJack you can troubleshoot a computer even if you can't load the GUI, or don't have a startup CD handy. AppleJack runs in Single User Mode and is menu-based for ease of use.

oneforty is a project of oneforty inc. Follow us on Twitter at @oneforty.

We're here to help. We give you access to the very best tools that make Twitter valuable. We help developers reach the Twitter community and keep providing the innovations that make Twitter better for all of us. There's an exploding ecosystem of applications and services for Twitter -- way too many to keep track of! Your home on oneforty is your place to find, rate, collect and share the best tools for you, and to tell the world what you're accomplishing with Twitter.

Amazing things are happening on Twitter. With the right tools, you can make amazing things happen too. What can YOU do in oneforty?!

Cocktail is an award winning general purpose utility for Mac OS X. It is a smooth and powerful digital toolset with a variety of practical features that simplifies the use of advanced UNIX functions and helps Mac users around the world to get the most out of their computers. Cocktail is installed at more than 200 000 computers world wide. The largest part being private individuals, but Cocktail can also be found at large international companies (Puma, Sony), educational institutions (Harvard University, University of Texas) or newspapers (The New York Times, Business Week).

The application serves up a scrumptious mix of maintenance tools and interface tweaks, all accessible via a comprehensive graphical interface. Most of Cocktail's major features are arranged in five basic categories. In addition, a Pilot lets you clean, repair and optimize your system with one click of the button.

I wrote The Twit Cleaner because I got sick of all the garbage on Twitter. Not just the spammers, but people who posted nothing but links all day every day, people who never replied when I messaged them, and so on.

The web isn't about pages any more. Now it's about streams, feeds and syndication. As part of our annual Best of Series, below are our picks for the most important RSS and Syndication Technologies of 2009.

Design and collaborate (in real-time) user interface mockups for your software and websites.

Twiangulate is a tool for discovering hidden tweeters, friends of friends (or friends of enemies), micro-influentials who only insiders follow... or sometimes just friends you haven't yet realized are tweeting.

For the past two years, Go2web20 has been one of the biggest web2.0 directories out there. We built this application to enable people to stay up to date with all the new & hot services that are born daily into the web. In many cases, Go2web20 has been the first to report the existence of a new application.

Did you know that your tweets have an expiration date on them? While they never really disappear from your own Twitter stream, they become unsearchable in only a matter of days. At first, Twitter held onto your tweets for around a month, but as the service grew more popular, this "date limit" has dramatically shortened. According to Twitter's search documentation, the current date limit on the search index is "around 1.5 weeks but is dynamic and subject to shrink as the number of tweets per day continues to grow."

As the number of people using mobile devices increases, so too does the pressure to ensure that our websites look good and are legible on a mobile device. The ideal, and unrealistic situation, would be to test on real handsets, but obviously this would be impossible for most designers. Fortunately, there are number of tools available online, allowing you to put your site through its mobile paces.