First of all, I really like this applicationm very great work. My first words was OMG.
As table import is great, I may add support for links in tables - maybe the link data is not a visible, but and interesting information for the importer.
Just another source may be simple lists (ul>li, ol>li). As it seems just a one dimensional data at first time, adding link information can make it two dimensional. Of course with some string manipulation (after the import) you can divide this data into more columns. Like "John Smith (USA)" -> "John", "Smith", "USA".
Importing definition lists would be interesting, too.
It may be a bug: if there's no table at all on the page, the menu item about importing the table exists in the contextual menu.
Andras