cmarshall
I don't know how Mailinator is coded, but I'd guess he hasn't written anything too custom for storing key/value pairs in memory, there are plenty of Java caching implementations, the key thing he has done is work out a way of reducing the duplication, which Redis won't provide out of the box.
Mailinator is a great example of having the minimal set of features required and no more. There's no logins, no setup steps and no guarantees. This allows Mailinator to run on such minimal hardware, adding disk persistence would add complication without making the product better, by definition the kind of emails you send to Mailinator aren't important, so if they're lost during the occasional restart it doesn't detract from the service.
The notes do cost more to produce, but the extra durability means that they last about 4 times as long (from memory) in circulation, so overall the cost difference is marginal for the government, but is an additional deterrent for counterfeiters.
[1] http://en.wikipedia.org/wiki/Polymer_banknote [2] http://www.rba.gov.au/banknotes/counterfeit/index.html
There's also tools such as this http://tools.pingdom.com/ from Pingdom that'll show the same figures from an independent network link.
From there, look at how long it takes to receive the HTML (not including any of the images, CSS or JS), if that's slow then it's likely that the web server is taking a long time to render the templates server side (it could also be due to a really slow connection...)
If most of the time is spend downloading a lot of images, CSS or JS then YSlow will highlight this and the areas that should be improved. YSlow will also highlight any issues you might have with not setting cache headers correctly.
If the site doesn't contain excessive images, CSS or JS, then the connection might be slow, the 500kb background image will give you a decent indication of the connection speed, though something bigger would be better.
Also, if you have access to the logs then most web frameworks will log out the time taken to render each page on the server.
As an aside, there's some details on wikimedia about how the geographically accurate maps are plotted: http://commons.wikimedia.org/wiki/London_Underground_geograp...
It looks like HP/Palm have learned from this and aren't going to make the same mistake twice, the more recent videos of the Touchpad show how much they've optimised the UI to remove the lag: http://www.precentral.net/webos-3-0-optimizations-make-smoot...
I suppose an attacker could bypass this method by turning off images in their browser though.
I can see where your app would be good, but I'm a developer and I have friends with English as a second language. If you had a video that showed someone catching up with a person they'd met on a holiday in another country or something similar then I think it'd put the problem you're solving in context better than the demo.
Companies look for experience since it demonstrates your ability, do you have a design portfolio, even if it's just mock up sites you've done in your own time to learn?
I've done a fair bit of hiring for the company I work at (unfortunately we're not hiring at the moment) and if a candidate with little experience can show us the kind of things they can build we regard it more highly than someone who has had a job for a year but hasn't shown much initiative beyond being given a task list and doing it.