Category to Tag converter allows you to convert the default category

[mdawaffe]

You can convert the default category into a tag either by explicitly choosing it from the list or by clicking "convert all".

Whithout a default category, new, uncategorized posts are given the category "1".

Possible solutions:

1. Allow a post to be truly uncategorized (i.e. not associated with any categories, or associated with a "null" category used only internally).
2. Not allow the default category to be converted to a tag.
3. If default category is converted, create new default category.

[markjaquith]

I vote for a blend of 2 and 3. Create the tag from the default cat, associate the posts, but don't delete the category or the associations with the posts for that category.

[ryan]

(In [6079]) Retain default category when converting categories to tags. fixes #4845

[ryan]

That implements Mark's suggestion of blending 2 and 3.