It would not seem courteous, believe me. Some fraction of the people who apply to YC are nuts. If you have a web site where you offer money to people who fill out an application form, nuts apply. Are we supposed to tell them they're nuts?
I often do not live up to it, but this is important:
The good news about Jesus can transform your life. Jesus died for our sins and rose again from the dead. If you become his follower, you will have salvation (moksha).
For a startup looking to attract co-founders I'm don't think this is very judicious. I'm not saying don't be religious just leave out any mention of it on company sites, that's what personal blogs are for.
1. No clear use for the product. (Please don't just tell me it's revolutionary and therefore unexplainable)
2. The interface is clumsy and I don't know what I'm supposed to do with it. (See Also: #1)
3. I don't understand what the deal is with the examples. Why do I want to watch a BBC broadcast with a tree-like timeline? Is the purpose of Juwo to annotate videos? (See Also: #1)
4. Why/when do people want to create a tree structure and attach text/videos/sounds to the tree nodes? This is all that Juwo seems to do. The use cases you list on your website are not compelling. While the use cases listed may be actual problems to be solved, a swiss army knife tree structure isn't the solution. (See Also: #1)
I'm sorry if the above list is harsh, but my personal opinion is that Juwo does not have any clear vision behind it, or is of very limited utility (e.g. only useful for you). I don't think it's worth working on further. Try something else.
It's easy at this point to appeal to the few exceptions that made it big even though it seemed like nobody wanted them at first. But note that these guys are the exceptions, most of the time the advice that the product sucks is probably accurate. Even if you were going to say "I don't care, I want to try it and see where it goes" -- well, it looks like you already have tried it for a few years, and it isn't going anywhere.
Again, no offense, but it's in your best interest to save the time/money/effort and move on to a new project. There's a reason you aren't getting users nor investors.
"we could not understand your idea. please get feedback as to its feasibility from your local university, or someone with experience in the software industry"
yc's already given you something better than what you'd get out of a canned one-sentence response: a fantastic resource in which anyone can put up their site and get a lot of feedback, for free, from a lot of smart people. 100% of the "hey news.yc check out my site" posts i've seen, including yours, have gotten useful, actionable feedback and have consequently improved.