Yee yee! The Zoosk iPhone App is here to feed your raging internet addiction!

As there are 50 million (and counting) worldwide registered users on Zoosk and 40 million worldwide iPod and iPod Touch users, a sizable swath of our Zooskers are also serious Mac people. Lucky for them, because our iPhone App promises to make social dating quicker, easier, and more efficient than, well, freaking ever.

Now you can Zoosk it up at work during that boring conference call or while you’re at the grocery store or while you’re at the gym or while you’re on a bad date with someone else (you’re just, er, responding to an important text) or in the bathroom or like basically anywhere you can find a signal. Which means, essentially, that you can flirt with online hotties wherever you go. With social networking, downloadable desktop, mobile, and iPhone applications, Zoosk is dating for the connected world.

Download the free iPhone App at the iTunes App Store online or right on your iPhone. If you’re not a Zoosk member currently, you can register and validate a new account, right on the application itself. After your first iPhone log-in, we’ll give you 30 free Zoosk coins. Use them to send a virtual gift to someone who catches your eye. Then get your thumbs ready for a flirting frenzy because that touch screen will put them to work!

Lastly, don’t be bummed if you don’t have an iPhone — Zoosk still has you covered on the mobile front. If you don’t have an iPhone, you can still access Zoosk on your standard phone with Zoosk Mobile. See how easy we make it for you to flirt shamelessly? What are you waiting for? Get out there and start flirting!

When we were designing this feature we had a feeling it will be a huge hit given the feedback we were getting from our users. However, it was really hard for us to gauge how much capacity we need to plan for and we didn’t want to spend a ton of money on infrastructure to accommodate a feature that might not turn out as big as you think it will (startups MUST be frugal to survive!).

So we decided to use Amazon Web Services for our photo processing subsystem to give us the maximum flexibility in terms of capacity planning while keeping our costs down. We had a few requirements for our design:

• Should scale horizontally
• Should be fairly decoupled from our existing data center (not expose our DBs to public network)
• Should be cost effective

In order to satisfy our second requirement above, we had to figure out a way to keep track of the in-progress-jobs without depending on our databases. Fortunately Amazon has a Simple Queue Service (SQS) that is very well suited for this purpose. We basically use it as a job queue for our photo processing.

Our ability to scale horizontally meant that we had to be able to add processing boxes on-demand as our load varied. We decided to utilize Amazon Elastic Compute Cloud (EC2) for this purpose.

Our process is conceptually very simple. Each photo uploaded by our users temporarily is stored on our data center. We have worker processes that copy these raw files to S3 for backup and also create a ticket in an SQS queue for it to be processed. Once in the queue, the next available processor on EC2 will pickup the ticket, process the photo, publish the output to proper location on S3 and then create a “done” ticket in another SQS queue. In our data center, we look for these “done” tickets and mark completed photos ready-to-serve for our users.

You might ask if all this complexity was worth it. It turned out that the photo feature was a big hit with our users. With millions of photos uploaded in the past few months, we are sure glad we designed the system this way and we love our ability to adjust our capacity on-demand for this feature.

Just to put the advantages of using cloud computing in perspective, I have summarized the size of photo data we have stored on Amazon S3 and also how much content we serve off of it in the following charts. Yes, those axises show numbers in TeraByte range . We would have really had a tough time to expand our data center to meet this load on top of the existing usage growth that we had to deal with. Off loading this work to Amazon has certainly paid off for us.

If you are interested in more Amazon Web Services usage data, checkout the 37signals blog as they chronicle their usage of the S3 service.