Just a quick point. You should always keep backups of any critical data that is stored on a third-party server - be it WTAworld, Hotmail, YahooGroups, or anywhere else. Data loss is always possible for a variety of different reasons including system failure.
However, this is the first time we have ever suffered any real data loss and we've limited it to around 48 hours of lost posts. Also note: we played it safe in the restoration procedure by going back a further 24 hours than possibly necessary to ensure all date corruption was eliminated (rather than risk another lengthy outage). That said, we maybe made a bad judgement call in trying to keep the site going for the last few days of the Australian Open - which has resulted in this limited loss of data.
We do apologise for any inconvenience this causes you.