Hi Friends!

Site description

http://codeabbey.com - is the site with collection of simple programming problems. Users could get some test data for each task and try to submit their answers. If answers are correct, problem is considered as solved by this user...

I've got the idea about two months ago and spent about a month on implementing the first variant, so that I put this to the hosting about a month ago and started adding problems to my site.

CodeAbbey do not contain online-judge like http://topcoder.com or http://codeforces.com - i.e. it checks only answer, not the source code. This is a kind of weakness but of course it allows me to keep things much simpler.

What Critique or Help I need
I am most interested in improvements for my idea and advises about functionality, though design hints could be important too (though I am not sure I can do much to design now).

An example of best advises I've got so far:
- to add the ability to point and report a mistake (English is not my native language and there are many of them, I know);
- to show the correct answer if incorrect one was submitted.

Also please if you have something to say about problems themselves - it would be very good. Do they look to primitive to you? Or you think some specific (your favorite) problem should be added here?

Important technical question - I now use markdown to add problems and wiki contents - so they look bit poorly. I've just tried add SVG to markdown in one of the tasks - it works, though I think it would be good to find some more suitable solution. Do you know some SVG preprocessor (like markdown for HTML) - or some completely different and useful idea for this?

thanks in advance,
Rodion