I would like to elaborate on Tony's comment above. I want to stress that when you are writing an article (which very very informative) for beginners at Spanish or any language, please write everything in this language correctly. I'm aware that in most non-formal language, the accents are not often used. But for the sake of learning a language correctly for beginners it is very important to clearly see when an accent should be used and in which case not.
So:

aqui --> aquí
esta --> está
¿Quien? --> ¿Quién?
¿Que? --> ¿Qué?
podria --> podría
le gustaria --> le gustaría
deberia --> debería

I hope that you can see the point I'm trying to make :)

Nice article.  It looks like there are a couple of typos.  Quention words in Spanish are written with a tilde:

“¿Quien esta aqui?” => “¿Quién esta aquí?”

“¿Que hacen ellos?” => “¿Qué hacen ellos?”

Dear Uri Quintal, you did not just miss the accents on the question words but on a number of other words as well: debería, podría, gustaría, está, aquí...

Indeed, as said before by a number of readers, it is fairly misleading and harmful to read an article that is full of spelling mistakes, especially if it was written by someone who claims to be a professional teacher as well as a native speaker of the given language. Please be more careful with that, accents are very important in Spanish and also quite difficult for many learners to use correctly, especially if they keep reading such confusing articles as this one.

Thanks for your understanding :)

I guess it applies to al languages, but the simple y/n question "¿Uri está aquí?" can get additional meanings:

 "¿Uri está aquí?" = we have expected somebody else to be here.

 "¿Uri está aquí?" = we have expected him to be somewhere else.

Generally such rhetoric question are expected to be answered negatively. 

Hi students,

it is very nice to hear from you.

I missed the accents on the question words, but I am glad that you guys have studied the grammar rule about the accents on question words. It is important for you to know that you are going to find them only when they are used as a question word, whenever you find them as a clause you should not use an accent due to its missunderstanding and its effect on the reader.

Thank you very much for noticing that and letting me know about it, I hope your Spanish skills are getting better and better and please keep on the good work,

My best regards,

Uri Quintal.