The data is not saved, sadly enough! I also have another forum, a gerbil forum with now more than 400 members. The previous gerbil forum was deleted due to the non-English post. Everything was lost, but we came back!
As long as we follow here the rules that Proboards states, we will not be deleted. A server crash will than be the only danger, but this is not likely to happen. I'm not sure if Proboards has back-ups....
But I've not heard yet of a Proboard forum that has crashed.
Can't you make a backup by yourself? I mean we have put so many heartblood work and time into this forum and it will be sad if the data will get lost some time. I've recently witnessed a crash at www.birdforum.net. Several hundred forum messages, photos and data entries were get lost.