When visiting https://phabricator.wikimedia.org/p/bd808/ currently, there's no obvious way to contact the user. In this specific case, there's a MediaWiki.org user page link, but many Phabricator user profiles won't have this MediaWiki.org link and even that path to contact is non-obvious (and dubious).
Phabricator user profiles should include an optional "contact" link or similar. This could go to MediaWiki's Special:EmailUser, it could be a mailto: link, it could be something else. GitHub exposes e-mail addresses on user profiles.
- Link to Special:EmailUser
- Rename "MediaWiki Userpage" to "Contact" (requires two clicks)
- Enable conpherence, which allows 1:1 private communication between users (also many:many; this part would need to be disabled). You can try it out in https://phab-01.wmflabs.org We haven't enabled Conpherence by default because of Wikimedia's default to public interpersonal communication. If the community thinks that enabling Conpherence is useful, we will happily enable it for all users. We agreed to enable it as an experiment for OPW round 9 participants (T834). @chasemp got a first good impression as well, suggesting already to enable it for all users. Quim thinks it is useful.