Saab,
It's not that good and that is not coming as a criticism but as an observation.
When the AF incident hit the press PPrune was being hit in rumors and news by around 5k + people on the one forum and you could not view anything on the site for around 2 hours without hitting retry. a minority of the time it was a timeout in the browser - the other rest of the time it was a message from the site saying too busy.
From an educated guess your mysql database is limited by the number of connections and the concurrent connections was exceeded thus pages could not be delivered. The overwhelming of the site should not have been a problem with the people on board as even at its peak of a few thousand its really not that performent compared to many sites.
I thought this was the very reason that web hosting should be outsourced to large server farms running the websites of lots of different companies ? Spreads the cost of the extra capacity needed for the occasional spike in demand amongst many websites, rather than just one having to bear all the cost. The same presumably applies to databases as well ?
Its the very reason you dont go for hosting - you go for co-location, you put your own hardware in the the POP (Point of Presence) on the internet - if you go for hosting then you will be one of many on the same cluster typically.
If you have a single box co-located you will still hit problems similar - what is required is a dedicated cluster - easily done with a number of Linux type boxes running apache but the question is should the owners of pprune spend the money to cope with the peak around an incident or just provide enough to keep the active community sufficient - I think the answer is in the question.
Given unlimited resources the site would be highly avialable all the time.