You can also select a text file containing HTML, and DragThing will extract all the URLs from the HTML with their titles, and create a dock for them. This is especially useful with things like your bookmarks file from your web browser, which is usually stored as HTML. You can export a dock of URLs to create a new HTML file you can open in your web browser.
If you have a dock with both URLs and normal dock items that you export, DragThing will create an HTML file for all the URLs inside the folder containing the alias files.