I don't think anyone can claim the evidence was destroyed. All of their posts have been archived in many places.
One may still be charged with obstruction of justice if there is a definite attempt to make unavailable evidence needed for a case, even if the unavailability is temporary until a suitable mirror can be found. It's such a broad definition for a criminal charge to have, and in this case I really think they would consider it.
Don't be silly. If a murderer burns the clothes in which he perpetrated the murder, he's not 'destroying evidence' in addition to being a murderer. Something must first have been determined to be evidence, before destroying becomes a criminal act. Neither are you obstructing justice by hiding evidence.
For similar reasons you are not compelled to incriminate yourself.
We don't have the 5th in the UK
Actually, I believe that is the case, although the charge pales in comparison to murder. IANAL, but the Green River Killer was convicted of contaminating a crime scene because he left false evidence to throw off investigators. From that, it appears that intentionally tampering with evidence of a crime - even if you created it - is illegal.
Don't be silly. No one can own an idea. The very concept of "intellectual property" is false to facts.
When you're facing the possibility of having multiple governments looking to 'come down hard' on you, I doubt destruction of evidence adds much to the mix.