[beezle]

If paper in question becomes fodder for the mainstream media (or at least the mainstream scientific media) then there is no reason why they should not have to defend their theory/arguments/speculations publicly in a less than formal peer reviewed forum, especially one of fairly high regard in that subject area.

[onhn]

There is a good reason: we should not be passing judgement on the validity of scientific work based on informal discussions.

[beezle]

Disagree. As just one example, the Solvay conferences of the 1910s-20s. Much of QM was developed by informal discussions, both written and verbal.

Likewise, most of the initial challenges to scientific papers/theories/experimental results happens informally and only later will there be a peer reviewed counter (if the original has not between withdrawn or modified before). Reference the OPERA ftl neutrinos for a recent example.