Firefox is meticulous about using the right application to display a MIME type, almost to a fault. Rather than displaying documents and movies in the browser when it would save time, it loves to launch Office or a media player. Sometimes we just want to see whatever we’re downloading directly in the browser. Not only is this a time-saving choice, it saves on system resources by not launching an external application.

Today’s Firefox addon of the day, the aptly-named Open in Browser (beta addon; registration required), will do just that. By adding a new option in the Firefox download menu, you now have the choice to launch certain universal file types directly in Firefox. These files include ASCII documents, movies which can use a browser plugin, images, webpages, and more.

Another usability addon today with the simple and stunningly ingenious Plain Text Links.

Rather than copying and pasting addresses that have not been hyperlinked into the address bar, Plain Text Links allows you to right click on the text to open the link. Common URIs like FTP://, HTTP:// and HTTPS:// are all supported with this convenient little number.

A little piece of me dies every time I’ve been selected to win two free iPod Nanos. Were I a lesser man, I would wither away as though I had chosen poorly in the search for the Holy Grail. Thankfully, gaining some control in the ever-growing morass of web advertisements isn’t any harder than picking the right cup. Today’s Firefox addon of the day, Adblock Plus, gives you that control by allowing you to block the advertisements you find most annoying. A click of the mouse is all it takes to eliminate that advertisement forever.

While the convenience of today’s addon cannot be doubted, it’s a double-edged sword. Be mindful of the fact that the longevity of established sites relies on the continued delivery of advertisements to end users. A site that delivers no ads is a site that no longer runs. Do your favorite sites a favor and leave their ads intact, but it’s totally okay to block all the ads on a site you hate so you stiff them out of a dollar.

Block wisely.

China Channel, today’s addon of the day, illustrates what life on the internet is like behind the great firewall of China.

Through the magic of a little routing, China Channel will submit all HTTP requests through Chinese servers which filter pages believed to inspire dissidence or contain anti-governmental messages. Users of the addon can then see what it would be like to live in a Big Brother state which keeps communications under constant surveillance.

While native Chinese users would typically be disconnected from the internet for fifteen minutes, China Channel allows you to continue the experience by relaunching the browser to obtain a new IP.

There’s no way to fully describe the limitless potential of Ubiquity, today’s Firefox addon of the day. Therefore, we shall do it in one sentence:

Customize the internet.

There. One sentence that describes what it does. Just go look at the video and download it.

In an internet landscape of meaningless, compulsory registrations, wouldn’t it be nice if we could simply avoid them and get straight to the desired content? For many years, the BugMeNot service has provided the solution for that wish by providing communal logins for the sites that require free registration to access complete content. Common offenders of this practice include IMDB, New York Times, and the Washington Post.

Today’s FireFox addon leverages BugMeNot’s thorough repertoire of these communal logins to broaden your access to free information. Skip the pesky single-use registrations that result in spam and get directly to reading the content you want to read.

Today’s Firefox addon of the day furthers our unhealthy obsession with Twitter, the hottest service in Web 2.0. While you could go directly to the website to send a Tweet, TwitterBar allows you to send the contents of your Firefox address bar as an update with the touch of a button. A new icon snuggled next to the familiar favicon star reveals the number of remaining characters and does all the tweeting with just a press.

While this addon won’t replace a dedicated desktop client, it makes quick tweets a snap.