submission to debian who uses wiki page

Hi there,

We are 100% using Debian for our commercial platform and I am trying to 
submit information to the who uses debian wiki based on the description 
found at here: https://www.debian.org/users/#submissions .

It reads on the page, 'In order to be added to this list, please include 
the following information in an email to [email protected] 
<mailto:[email protected]?subject=Who%27s%20using%20Debian%3F> 
(please don't change the subject line).'

Sorry, what subject line? Is there anywhere stated what the subject line 
should be? If so, I cannot find it. Also, I would like to know if I need 
to be subscribed to this email list before I can send new submission.

Thank you in advance.

-- 
Kind regards,
Miklos Quartus
Linux System Engineer
DeliveryHero, pizza.de platform