On seeing a headline like this my first reaction is always "there are 100 startups in Australia??", followed upon reading the list by "apparently not".
The rankings of some of those sites are a real worry. A site with an Alexa rank > 1000000 doesn't deserve to be on a top list of anything.
They'd be best to limit it to 50 or even 25.
It irritates me when I see a list of startups with traffic estimates beside them. (A) Traffic doesn't necessarily indicate anything. (B) Traffic isn't a useful comparison unless they are doing the same thing. IE if you are comparing newspapers to newspapers or online Shops to online shops, fine. But this is comparing one company selling enterprise software at 20k per customer (that may never see the site) to one selling books online to another that writes a blog. It's ridiculous.
Exon Mobil gets fewer pageviews then Google.
But for comparing AU sites, these numbers are near enough to useless, because they measure "global" traffic (in practice mainly USA traffic), and make no allowance for AU-specific traffic patterns.
Our site (yet to be properly launched) has an Alexa rank higher than Docoloco and a Compete rank higher than OzBargain. I know for a fact our actual traffic is much lower than these sites, and it's the relatively small volume of USA traffic we've been getting that has skewed the stats.