Some discussion pages don't appear. Why does it happen?
When I clicked an old discussion page it appeared as follows:

Oops, page not found
Sorry, that page doesn't exist. Please check the link and try again.
You can also try going back to the italki homepage

Question

Some discussion pages don't appear. Why does it happen?
When I clicked an old discussion page it appeared as follows:

Oops, page not found
Sorry, that page doesn't exist. Please check the link and try again.
You can also try going back to the italki homepage

Answer

Here is the discussion page. http://www.italki.com/discussion/81953

I don't think there's anything wrong in it from the words I see before I click it:
 Is this app "Line" popular in your country? For Instant Messaging.
This is the app's website.http://line.me/en-US/ It's really popular in Taiwan to chat with friends.Just like I know in China "微信" and "QQ" are common.How about other countries?? ^_<

Answer

Because they may be against the terms and conditions of italki website.