Import links/blogroll in OPML format and allow them to be inserted into their proper link categories.
WordPress doesn't even support sub-categories for link categories. If you try to upload an OPML file that is sub-categorized, you can probably expect strange behavior. However, depending on the structure of the file, you may still be pleased with the result.
So far, I have tested WordPress generated OPML files, and Firefox (with the OPML Support add-on) generated OPML files. If anyone has trouble with an OPML file from a different program, let me know all about it and I'll see if it is an easy fix.
No. the category check is case-insensitive. Therefore, you could have a link category named 'Cars' in your blog and a category named 'CARS' in the OPML file, and those links would be properly inserted into 'Cars'.
No. At least not yet. I built it on 2.7 and poked around trying to get it work on 2.6 but did not succeed. If people actually download this plugin, maybe I'll work on some backwards compatibility.
Yes, you'll can put the main plugin file
import-blogroll-with-categories.php in the
mu-plugins directory to enable it
automatically for all blogs. You'll just have to put the file
bwc_opml.php in a sub-directory and change the path of the
include in the