I'm thinking if the question the answers on which would include the showcases of great user experience is allowed?
I have a small bunch of bookmarks with the sites and apps which I found beautiful in the sense of UX.
Unfortunately no. UX Stack Exchange is intended to be a Q&A site, not a repository for information on design. I recommend providing in http://www.reddit.com/r/design
That's what your personal portfolio is for! :-p
... Seriously, though, Q&A goes here. You can link to nice examples in your answers, but if it's not relevant or (worse!) it's old, it's not going to be all that useful to the rest of us.