In most other systems, the ability to directly contact a user is fairly easy.
Bugzilla had email links.
Slack/etc has direct person chats, and they are private (c.f. T150732)
With Phabricator, navigating to the "user" page of a person provides user links to MediaWiki.org and LDAP (actually Wikitech), which are public spaces, and may not be suitable.
Currently to start a Conpherence I believe we need to go to https://phabricator.wikimedia.org/conpherence/ , click new room, which loads https://phabricator.wikimedia.org/conpherence/new/ , then add the persons username.
It would be great if there was a "Start Conpherence" link on the person user page (e.g. https://phabricator.wikimedia.org/p/jayvdb/ ) - it could load a prefilled https://phabricator.wikimedia.org/conpherence/new/ if the two people havent communicated directly previously , and ideally it shows a list of existing rooms that both people are already in, so it is easy to choose an existing room which may be appropriate for the intended message .
(Also, it would handy if the Wikimedia Phabricator collected registered IRC nick handles, and displayed them there also, given that is our main mechanism of technical adhoc communication.)