Also, the Deputy senior mod gave a good explanation in a thread in JB on why they deleted certain posts at certain times in MH370. Worth reading. - and concerning that thread movement appears to be driven by someone's idea of a 'good theme', no doubt boosting ad revenue for those who benefit.
The editing is, as usual, bizarre - I have seen perfectly reasonable, intelligent and useful posts disappear (presumably not fitting the 'script') while the tonnage of repeated questions, incorrect or well out of date info, stupid questions etc etc appears to be 'ok'.