These days there is much noise about a new term "Clickjacking".
I think the term is new in itself not the the way it executes. Clickjacking is a form of UI redressing attack and equivalent to XSRF attack. Like XSRF attack it also uses the credentials of already authenticated user to execute the request successfully because the server can't differentiate between user's request and an extranal hacker's link. Then came the mitigation to this XSRF attack to use page-nonces,randomly generated one time hashes or values, which are included in every page request-response uniquely.
The main risk imposed by Clickjacking is the ability to bypass nonce-based XSRF defence. In the Clickjacking attack, the user interacts directly with the target Web page, which is visually hidden, so all transactions include a valid nonce and the attack is left undetected.Clickjacking has proved that our theory about nonce-based defense and where its weaknesses lies is true.The main risk imposed by the clickjacking attack is the ability to bypass nonce based XSRF defence, which is considered the most robust protection against XSRF attacks.
Since the vulnerability that allows clickjacking attacks resides in client software(Web Browsers) and not in Web applications, there is no complete solution except of presenting fixes to the vulnerable platforms.
Major vendors products are said to be affected from this vulnerbility.That's why security researchers had deferred their presentation on how to exploit it after receiving request form the vendor.
Web Keys can be used to mitigate the problems to some extent.Complete defence is still awaited.
Imperva paper gives a great detail of the issue.