SoundCloud , the beautiful, easy-to-use widget becoming more and more ubiquitous on the web, has reached 8.5 million users--including 50 Cent  and Russell Brand . The last million of them were added in the span of 45 days.
For SoundCloud co-founder and CEO Alexander Ljung , a few stand out, incuding the sound of 10,000 bats gettin' it on.
Ljung also tells Fast Company he's keen on the way journalists have used SoundCloud to capture stories--such as ABC News Radio's Dan Patterson  recording the sounds of Occupy Wall Street in New York. And he's been impressed by the way candidates in the San Francisco mayoral race have used it to spread their messages and respond to potential constituents. SoundCloud has also highlighted the sounds of cities and towns across America (see: SoundCloud Local: Ann Arbor ).
Ljung, a 30-year-old, self-described "sound geek," believes audio will surpass video on the web. "There's nothing that's as simple to create than sound," he says. Also, "It's not a good idea to drive a car and watch a YouTube video at the same time."
He's put his money where his sound-maker is, too, relying on a business model supported not by advertising but by paid subscriptions to premium services that allow bigger uploads, easier sharing, and more. He declined to give numbers or percentages of premium users, but he did point us to a few of his favorite SoundCloud embeds, below.
One SoundCloud client  used an underwater mic to record the sounds of spring--specifically, ice melting. "It's a beautiful recording when you listen to it with headphones," Ljung says.
A recent SoundCloud blog post rounded up ice cream truck music  from around the country, a favorite of Ljung's, he said. The one above would given even the most ravenous soft serve gulper the chills.
Where other than San Francisco does it make more sense to use a web widget to cover the mayor's race? KALW News there has posted a bunch of clips allowing all sorts of candidates to get their messages out.
"We had a conversation recently about the robotic voice on the BART [San Francisco transit] system," Ljung says. Just for the heck of it, he searched for it on SoundCloud. It was already there.
[Image: Flickr user iSLD ]