Thx for your time, this is the kind of comment I was looking for:

* Make the logo link back to the index. did that, * Don't make me register. I'd like to try the problems but am not interested in saving my results. I can't try such and such problems because I need an account simply to validate my answers.

I am going to allow unregistered users to solve problems, however, I have to uglify the form with captcha,

* I'm not sure if displaying the last 10 on the front page is a good idea... if I come back tomorrow to check this problem I saw there, will I have to go to page 2? ProjectEuler's page has them in increasing order. My thought behind this was if u come tomorrow I don’t want to see the same problems (hopefully solved problems ;-) )

* Remove some text. “Average User Rating: easy ” can be transformed into “Easy” in the blue problem header, for example. Make it easy to see and filter. You can use images there as well, or colors. Difficulty: Green → Orange → Red.

Great point, will do that.

* The list of solvers is unreadable. Why is it in italics? What's its maximum length? You could use something like the “following” list on twitter: lots of small icons (24x24 or so).

* Also either display the login or the name, not both.

I wanted to display the name, but also didn’t want to force the user (when registering) to go to a painful process, hence, not all the users have names.

* Why do you limit top user to 10? It makes sense for problems as they take a lot of space, but you could easily display users hundred by hundred.

I wanted to have top 10 ;-),

* Are tests made of problems? What if I've already completed the 5 problems a test contains when I start it? Do I automatically win?

No, you have to answer them again.

* I don't have an account so I can't check, but do you allow LaTeX in the discussions on each problem? Is there an option to add code? Is it allowed? Is it colored when entered?

At this chapter there is still more work ahead, currently only some special math characters are supported (like x^(y) – power, x_(1) , ..)

* The white space on top is way too large.

agree

* Is this a website or a “framework”? Revise your wording on the right.

English is second language for me, so framework sounded cool, I guess I have to look it up in the dictionary.

* In general, try to avoid “database views”. I don't know how to word this better, but don't put “fieldname: fieldvalue” in your texts. For example in the submitter name: “test submitted by $name on: $date”. You don't need a colon here, this is not how you would write it in a letter for example.

agree

* Put all your tags in lowercase. Fibonacci stands out and Einstein is missing a capital E.

agree

* Are you displaying ALL the tags? What will happend when you get to a thousand?

No, only top 100

* Could the problems be put in different math groups? Set theory, algebra, geometry (can a submitter upload images?), trigo, etc. Beware, this could be confusing: should I put this in the “Algebra” category or tag it as algebra?