Some people need their every thought to be shared and recorded for all time, and for those digitally gregarious folks, TweetFast is a convenient and productive tool. The MacOS extension puts a Twitter function directly in users' menubars, allowing them to send out tweets without even opening an app or going to the site on their browser.
As with any form of inspiration, it's impossible to know when the impetus for a tweet will strike. For those who find themselves frequently inspired to shout their concatenated thoughts into the digital abyss, opening up the Twitter app or website is a relatively large interruption to one's workflow. With TweetFast, there's no interruption whatsoever, as the menubar is visible on MacOS no matter what else one's doing on the computer.