Is it possible to limit the maximum frequency at which words are studied? Some words are scheduled every 3 minutes because I don't know them yet, maybe it would be more productive to delay them and work on what I already know.
Seeing always the same words and not being able to try some new ones ruins the experience a little bit.
Thanks

Forcing you to learn the difficult characters is Skritter's strength.

Try to spend some time on these characters, e.g. by looking at the decomposition and mnemonics. Delaying characters, e.g. by giving good marks, might be nice in the short run, bit in fact it only increases the actual number of repetitions in the long run.

As has been said, you can delay items by marking them as "good", but this will just have the opposite effect: increasing repetitions in the long run.
Instead, if you really don't want to learn a character/word, just delete it or - better - study it with increased vigour.

Also, if you keep getting the same characters because you don't have any other characters due and just keep getting a couple annoying ones wrong, you can add some new words manually by pressing the +-button.

This is however, only a suggestion to avoid frustration in the short run. Additionally I would agree with 穆儿, it can really help to decompose characters or make up ridiculous mnemonics for them.

Or better yet, use the word popup and delete the character that's giving you all the trouble. A lot of the words that are hard to learn just aren't worth it yet.

Well I'm studying HSK in order. I do want to learn them, but it's no use showing the character every 3 minutes, it would be better to show it again the day after.

These initially short intervals exploit the psychological spacing effect, the process is called "Spaced repetition". Increasing them or neglecting the existence of the spacing effect would make the learning process less efficient and thus, in the long run, increase the time spent on the character.

See: http://en.wikipedia.org/wiki/Spaced_repetition

I know about SRS. The problem is that it's good for remembering, not for learning. When you don't know a word , there is no limit to how short the intervals can be.

There should be an upper limit to how often a word can be reviewed, eg once in 10 minutes.

This way you can still enjoy discovering new words, and are not stuck with unknown words to review.
You keep the motivation which is essential to learn.

IMHO this is an important issue as it affects the core UX. Also I've been using Skritter since the beta, and it is one of the reason why I stopped studying several times. I'm probably not the only one in that case.

sometimes I just start to dislike certain characters and don't want to see them at least for the same day...so I can understand pepitof2...

Ever noticed the eraser? When I hit a difficult character, one that I never get right and that continues to pop up ever so often, I write it in skritter 5 to 10 times in a row using the eraser. If that doesn't help I sometimes take a piece of paper to really get a feel for this character When it pops up again after a short while I can reproduce it most of the times.

I've been irritated with unknown characters like that as well, but they actually give you some good motivation to study more effectively, because if you don't figure them out after a while, they keep annoying you until you finally do figure them out. Plus, if you are just hopelessly stuck on a character in Skritter, just pull out a notebook and go old school to get it in your head long enough for the SRS to kick in.

Any updates?

We've never had the complaint that people want to see the words after a long time period before; if anything, it's the other way, that people can't remember characters after a couple minutes. The only way for you to get the system to believe you that you want to see unknown characters after a longer wait is to mark them right instead of wrong when you don't want to see them just yet (by pressing 3). Do this only on the second repeat in close order, without actually trying to remember the word. Then it should increase the interval to something close to your desired ten minutes.

Eventually, this will increase the scheduling system's initial wait after a short-term wrong answer, so they don't come so often by default. It won't keep going higher unless you actually can remember them after ten minutes a reasonable portion of the time, though.