We are very excited about the fact that this awesome product uses Aspose.Words for .NET to open and save documents. At the moment Buzzword imports and exports DOC, RTF and WordprocessingML. These conversions are performed by Aspose.Words.dll on the server.
From the Virtual Ubiquity website:
"Buzzword, the first real word processor for the web, is a breakthrough in collaborative authoring for documents that matter."
Our recent release Aspose.Words for .NET 4.4 supports export to Office Open XML that means you can expect Save As DOCX will be available in Buzzword in the near future.
We are also working on DOCX import as well as support for Open Office (ODT) documents. Hopefully, this all will make its way into Buzzword.