Feature Groups, Secondary Categories Questions - Point Me To Sites That Use Them?

Would greatly appreciate it if someone could point me to a site which uses feature groups and secondary categories so I can better visualize what my site could gain from using them. Both would quite naturally apply to my products but they would not be necessary as the site is at this point not too complicated and could be organized reasonably nicely with a flat category list and a list of features which apply to almost everything. I'm thinking of groups and subcategories because the better these things are organized the easier maintenance and expansion will be going forward.

About feature groups, if features are grouped are they available at all as individual features, or are they only now available as a group, all or nothing? If I group them I will need to recode my Features calculation for generating an import CSV. Presently a feature field with no groups looks like this:

“Artist: T[Linda Mason];Brand: T[Linda Mason Originals];Medium: T[Vinyl soft body];Height or Width: T[“25”];Edition Type: T[Limited Edition];Edition Size: T[250]”

According to knowledgebase the general format is:

{Feature ID}(Group name)Feature name: Feature type[Feature value];…

Group name is obvious. Is “Feature ID” just the “Feature code” on the General tab when a Feature on the list is edited in Products::Features Admin?

[color=#555555]All features that you import must be in the [/color]{Feature ID} (Group name) Feature name: Feature type[Feature value][color=#555555] format, where [/color]Feature ID[color=#555555] - ID of the feature, [/color]Group name[color=#555555] - Name of the feature group,[/color]Feature name[color=#555555] - Name of the feature, [/color]Feature type[color=#555555] - Type of the feature ([/color]C[color=#555555] - checkbox, [/color]M[color=#555555] - multiple checkboxes, [/color]S[color=#555555] - text select box, [/color]N[color=#555555] - number select box, [/color]E[color=#555555] - extended selectbox, [/color]T[color=#555555] - simple text, [/color]O[color=#555555] - number, [/color]D[color=#555555] - date), [/color]Feature value[color=#555555] - Value of the feature (several values can be delimited by a comma). Several features must be delimited by a semicolon. Note, it is required to create features on the [/color]Product features[color=#555555] page before (!) applying them to the products.[/color]