That depends: For Firefox2
bookmarks it was very easy, they could either be shared and used simultaneously, or copied and used separately:
Help > FAQ > netspace bookmarks brings you here:
Not sure but guess the "Netscape" bookmarks system was adopted for earlier Firefox versions, that's why it's still called that way, but at any rate this was valid for FF2.
stores them differently. You can EXPORT them from Firefox "to html"
, and then you have the FF2 version again which you can use in K-Meleon.
No idea if FF allows in some option to work with their old system too