It doesn't look like the owners have shown up here yet. If they do, here are some (hopefully helpful) suggestions from a target user who purchases proto pcbs all the time over the internet:
> Examples: 4cm by 2cm, red PCB: $12 for 10 copies - This should go on the front page. The price is so low that I thought it might be $12 per copy, but you have to order 10.
> Return customers - You like it dirty, you're back for more - Ok, for $12, I guess I can put up with this kind of stuff. But you're not helping yourself here.
> Is my design safe? - Your board will go to a cut-rate prototype PCB factory in China. In all likelihood they have too much volume to give a crap about what's on your PCB, but if this is a concern PLEASE FIND ANOTHER SUPPLIER. - Well, this one is actually funny, but in a sad, tearful sort of way. Why remind people of sad truths? All it can do is take away what could have been a potential customer.
> Shipping is by Hong Kong Post (or similar), which takes 4-30 days - This is great for a lot of people, but there are a whole class of other people (maybe 50% of your audience) who would gladly pay quite a bit more money to get something faster. 30 days is a long time. A different shipping option, even if it was $35 or so, would go a long way here.
PS Good job with the site! The cost is so shockingly low that it certainly gets your attention.