Last night's database maintenance (or rather, urgent repairs) was not planned. Forums was still accessible but new threads/posts were turning up blank. Site was hence closed for repairs which took much longer than expected to complete (2 hours!!) and that could not be helped either.
Sorry but no chance for any warnings in such cases. For scheduled maintenances, an announcement will always be (and has always been) made beforehand.
Thanks for everyone's patience and support.