The issue with online poker is the same as table top poker.
Online == server admin simply looks @ what cards you are holding.
Table == Cameras, bystanders sending signals.
Both == Collusion.
As another user mentioned, you can definitely prove the deck was shuffled randomly but you cannot prove or disprove admin honesty in this situation. This is why I only play with small change, Im after a cheap thrill and due to my cheapness Im not an ideal target for a scammer. Its why this is such a classic scene in movies:
Pub + poker table = flip table + gun shoot out.
Wise move. Dooglus points out
Mental poker, which looks promising. Setting up a properly shuffled deck looks incredibly convoluted from an engineering perspective, but the basic idea is sound ... best I can tell. There is definitely a market for it, so I think it's only a matter of time before somebody develops something along these lines.