Try these simple steps:

1. Open this page
2. Confirm that posts/all actually returns all posts and the optional tag argument is used as a filter
3. Open this link http://del.icio.us/api/posts/all. Fill in your delicious account info.

At this point the page has to be full of your posts data but it isn’t. So try to refresh it and et voilà some other random posts.

You can also pass the tag argument in the URI but it’s the same thing.

Is it my account to be broken or the delicious API is?

UPDATE: it seems that the bug has been fixed by the del.icio.us team. Great

UPDATE #2: no way, the delicious API is gone random