* dalanicolai <dalanicolai@gmail.com> [2021-02-27 23:53]:
> I think all packages fulfill your requirements. So I would say it depends
> on how many contacts you are managing. I have some experience with
> org-contacts, and I find it very convenient and straightforward. It is also
> very convenient to just use org-mode, i.e. a plain text file, for your
> contacts.

That may be convenient for friends or family, but is not a good idea
if such a contact database is to enlarge due to marketing actions.

People who collect leads and manage relations with many other people
must have straight way to manage contacts, and similar to well known
CRM systems such as SugarCRM or others. In fact contact management
could be managed by external program and database accessed through
Emacs. Though I do both with Emacs. And I like to access database from
shell as I do not use only Emacs as editor. As the database is
liberated from editor it allows access through any software or
programming language.

> Every contact is a headline and you can add any kind of property
> or tag etc. you want. Also anniversaries get added to the Agenda. You can
> very easily jump to the right contact, using imenu or swoop/swiper (I use
> `SPC j i ` in Spacemacs. So if you have less than say 300 contacts (I have
> really no clue about the number of contacts that will still work smoothly),
> then depending on how die-hard you are, I would recommend to start with
> org-contacs.

More important is how fast are contacts coming into the database. If
there are just 100 per year, then that will work well.

But marketing action of 23 hours have provided me like 1700 contacts,
so there would be no way that I ever keep up with text or hand
work. That requires automated insertion of contacts into the database,
and I use local database. Online lead capture is sent PGP encrypted by
email and emails are automatically processed and leads entered into
the local database. Placing contacts online is insecure IMHO, no
matter what is advertised about it.

> You can use org-vcard to import contacts, and org-vcard claims to
> support exports too but I did not test that yet.  Anyway, I think
> you won't loose much time with setting up org-contacts and from then
> you can slowly check out and study the other options.

I am attaching `rcd-vcard.el` that uses PostgreSQL database and my
schemas to export vCards that work nicely with
Android/LineageOS/Replicant devices. Package alone will not
work. Functions may be useful for some people to modify them as they
wish. If somebody wish to really install my system, I will be helpful
in private chat or email and guide person until it becomes functional.

Jean