Is someone can help me create example?
- front-end registration
- front-end login
- front-end adding any content (it could be guest post or authorized user)
- is there any possibility create comparing content (like products in online shop)
Will be very appreciate for any help!
4). Don’t know what you mean with this question, but there is an online shop module for Kirby…
@1n3JgKl9pQ6cUMrW: Since when is a Wordpress plugin compatible with Kirby?
Regarding question 4).;
I think OP want’s to filter products / content, based on taxonomy and parent-child relationships, in conjunction with an organic data-structure powered by some semantics?
This can be done with some meta-data (in a custom field, or from within the meta-data page) in the panel (or simply upload the appropriate text-file using (s)FTP).
Well, this is a Kirby forum, and I take it that if someone asks for a solution here, that it is Kirby related. A tip to use Wordpress instead, is not very helpful in this case.
Tips to WordPress can be useful, when someone it looking for a solution - not for a CMS 
But I will delete my post, referring to WordPress - since you kindly mentioned it 