Proving knowledge gained

Dear Articulate Community,

I've been using  e-learning for years with websites that have all sorts of courses in information technology, design, project management, coding, computer design computer infrastructure etc.  on various websites.

I'm sure you've seen these sites.  The user logs in and plays a video and gets instruction either from an instructor or views screen movements and actions to learn applications like Photoshop.

But when you learn outside of a formal classroom how can you prove that you've taken the course?  How can you prove to an employer, for example that, that you've viewed a webcast on Photoshop and now have practical knowledge that is applicable to the job advertized?

There's been such a revolution in online learning but what about validating that the student has command of the new subject matter after taking the course?  How would you even gain acceptance that this validation is legitimate?

I understand why this might be hard to do online. 

Administering the test remotely has many challenges. What value would such a test have if there is no proctor present to guard against cheating?

How would you prevent brain dumps?  How can a tester guarantee that the test taker hasn't harvested the test questions and uploaded all the questions online for profit?

I'd love to hear your feedback on this topic.