I love the blue theme, but I agree with the other reviews and you should try making it green, but try using the graphic options that where used in the blue theme (shadows, icon sizes, etc.) Try changing the blue bar at the top with a ribbon to give it more of a charitable texture to the site.
Love the concept.
At first I preferred the blue but after seeing what the site was about I think the green is more appropriate - the green associates with money which is the overall goal.
I will sending this site to my sister who runs a non-profit and could benefit from this site.
Nicely done.
Blue one is calmer, cleaner, safer. Green is more energetic, more loud.
If I were to choose for myself and assuming I would use the site more often than once per week I would go with blue. To me the green would get too annoying if I am to use the site each day.
However you should think first what color appeals to your target group age (I am above that age). Did you try other shades of green? Let's say one more electric, another more calmer, organic?
My vote is green. I think the gold accents lend themselves more to the overall coin concept that you are promoting.
As far as business model is concerned I think it's a very interesting concept. I fear that even though you have a very simple way for people to donate money, you're still going to have a very challenging task of reprogramming people to move away from utilizing the conventional google.com or yahoo.com just due to the fact that so many people have condition themselves to go there.
I think you need a "make this page my homepage button" so that when folks open their browsers to search they will use your site by default.
I also think you could greatly benefit from a kindcoins.com toolbar that integrates with ie and Firefox.
I really like this idea and concept.
However, it's too close to the coinks branding and because the idea is kind of similar in that it's a rewards scheme, I think you may need to look at differentiating yourself a bit more.
Overall it does look lovely though - just a different font should do it.
http://coinks.co.uk/
I'm a little unsure of the ethics here. Are you making money from ad hits and then recycling it for charity use?
Cool design, i love the green one because it gives the right impression on what the website is focused on.
The vector arts are awesome and the design in general makes it clear what the website is all about.
If you would change something it would be the header. It looks empty and should look great if you filled in whit something creative. :)