Just an avid reader. Mostly SF/Fantasy, some hobbies, paranormal, urban fantasy and lighter, fluffier things.
The link to export your data in Jacquie's farewell doesn't work for everyone.
When you are logged into Leafmarks, glance to the right at the silhouette/profile icon (circled in screenshot below), click to see choices for your profile settings, import/export and logout. You want the import/export one. Then scroll down to the bottom "Bookshelf Export" option.
The link I see for it is https://www.leafmarks.com/lm/#/import which may or may not work for you but so far that menu does.
It will create a *.tsv file (tab delimited ascii format) that most spreadsheet programs and book sites will pull in. Past experience says if on first try doesn't import on sites you want to import to, see if they have a sample file or import other site tsv or csv files -- then pull the headers from the tsv/csv files that site likes and adjust the Leafmarks data to fit.
Depending on the site, I might be able to help you with more instructions (don't know all of them). Comment on one of my posts here or message me on one of my other sites -- haven't gotten booklikes messages to work for years since they first introduced a book database.
Feel free to reblog.