We just rolled out HTML formatting support to messages, and comments on todo items. Now, when you get a message with text in bold, italic, or embedded lists or tables, that formatting will be preserved in the messages posted to Basecamp (we used to only post plain text).
We’re not supporting all HTML formatting at this point. The big reason is that it was a lot of work to build something to clean up the HTML that is sent by Microsoft e-mail clients. We’ll likely be adding in additional support in the future as things go along.
If you notice a bug, or would like your favorite HTML tag supported, drop us a line.