For all the Export/Backup options except PDF, Wikispaces exports a folder "mainSpace>discussion". It contains the Comments and Discussions on each Page. Each file is the complete thread for a Page's Discussion topic or for the selected text thereon in JSON format. For my 277 Page site, 194 files were exported for 94 of its Pages; some Pages have multiple JSON files because there were multiple Discussion topics and/or multiple Comments on the Page.
The Export thus separates the exported Page from its Discussions and Comments. This may be unimportant for some sites but for others the loss of the relationship is critical. The JSON files do list the Name or Title of the Page to which they refer. Comments type JSON's also refer to the highlighted text on the Page to which they refer. Therefore it is technically possible for Discussions and Comments to be reunited with their Pages in the target site. This may be as basic as incorporating them into the exported Page's static HTML file; ideally, they would be converted into the corresponding Discussions and Comments systems in the target site.
The EditMe service demonstrates the conversion of Wikispaces Discussions into EditMe Comments but, as yet, no conversion of Wikispaces Comments. I do not know if EditMe has the ability to comment on specific text within the Page.
Discussion of Discussions and Comments has been ongoing under a more general topic. I'd like to consolidate and continue it under this more specific one.
Looking to move SQLite Tools For RootsMagic from Wikispaces