Comma separated lists of tags.
tag1, tag2, tag3
Tags can be sub-divided into groups using a forward-slash.
tag1/group1, tag2, tag3
If you want a bookmark in multiple groups within a tag, you need to repeat the tag.
tag1/group1,tag1/group2, tag2, tag3
Tags can't be nested, only a single level of grouping is supported.
tag1/group1/subgroup1 <-- this will NOT work