Maybe related: Implement "Badges" or "Medals", for annotating special users https://secure.phabricator.com/T6526

Phabricator (Upstream)?

Have we considered this might have the opposite effect: e.g. a giant "user is newb" sign might make the user self conscious

In T64324#1313744, @Bawolff wrote:

Have we considered this might have the opposite effect

See my sentence above: "But it could also be branding users as "newbies" who might not like that tag."

Upstream comment regarding using the implementation of badges for this: https://secure.phabricator.com/T6526#116150

In T64324#1314126, @Aklapper wrote:

But it could also be branding users as "newbies" who might not like that tag.

I still think the advantage would be bigger. I find myself clicking task reporter names to check whether it might be the first time they use Phabricator in order to add a "Thanks for taking the time to report this" first sentence to my reply.
If their name had a small star next to their name (or something like that, though that would interfere with the use of stars for Watchlist stuff in MediaWiki) for, say, their first five activities in Phabricator and then the star would get removed, all established users could at least get to know that their actions on the task should even more have an explanation.
Hearing concerns that Phabricator is not welcoming (not only for social but also for technical reasons though as it's a different interface than a wiki), many established users don't have the time to always explain their actions (e.g. just marking a task as duplicate without any further explanation) and such an indicator could at least help creating awareness: "be more patient and consider elaborating".

Why don't we ask the participants of the last GSoC and 2xOutreachy rounds? They have a fresh memory of their first days in Phabricator as a newcomer.

We could also ask to a semi-random sample of actual Phabricator newcomers, say one every five new users in the past 30 or 60 days.

With Conpherence, doing this is quite trivial.

At least we would have other opinions.

Github recently implemented a similar feature.

https://twitter.com/benbalter/status/845305265159376896

In T64324#1712610, @Aklapper wrote:

In T64324#1314126, @Aklapper wrote:

But it could also be branding users as "newbies" who might not like that tag.

I still think the advantage would be bigger.

Good!

If their name had a small star next to their name (or something like that, though that would interfere with the use of stars for Watchlist stuff in MediaWiki) for, say, their first five activities in Phabricator and then the star would get removed

Is there a feature for assigning/removing badges automatically in Phabricator?

Is there a feature for assigning/removing badges automatically in Phabricator?

No.

Then I would decline for now and reopen if/when Phabricator has this feature. Manually maintenance is quite of a blocker here, regardless of the usefulness of the idea.

Moving to the upstream project; task is already lowest priority. (It's still something I'd like to see and we keep tasks open in downstream.)
If this is about reducing the Developer-Advocacy backlog, feel free to remove the project tag.

(This ticket came back to my mind when reading WMF's internal conversations on communication ("ERC").)

IIUC, GitLab only uses a 1 indicator in some circle/star next to the username for someone's first patchset (and not for tasks/issues/tickets etc):

For the records, OR criteria in Mozilla Bugzilla (Perl code now at https://github.com/mozilla-bteam/bmo/commits/master/extensions/TagNewUsers ) are:

# users younger than PROFILE_AGE days will be tagged as new
use constant PROFILE_AGE => 60;

# users with fewer comments than COMMENT_COUNT will be tagged as new
use constant COMMENT_COUNT => 25;

If implemented, this visual indicator should also be applied to non-comment actions (e.g. status/assignee changes etc).

Note to myself: see also discussion in https://bugzilla.mozilla.org/show_bug.cgi?id=1159883

Not a convincing usecase for upstream.