When the site was originally set up by Cynric he obviously looked carefully at all the hosting options, and apart from the current hiccup they have been remarkably good. The hosting plan includes a significantly sized storage option, with the current issues I have been cautiously looking for alternatives and it's very difficult to find anything comparable. At the moment we are currently using about 25%-30% of our available storage space - so plenty of room left yet.
So to answer your question I have never had to delete or remove any posts due to size limitations. Some posts and threads have been deleted by the request of members leaving the site and wanted their posts to be removed. Some threads have some missing images but that is because they were just links to photobucket/smugmug accounts that have since been deleted when they changed their pricing plans. Which is why I would always encourage members to upload photos directly to the site.