Responds on Chat room, but not DM, but the debug mode says it did send it out:
root@host:/var/log/upstart# tail -f hubot.log
[Thu May 08 2014 23:35:46 GMT+0000 (UTC)] WARNING @userForId() is going to be deprecated in 3.0.0 use @robot.brain.userForId()
[Thu May 08 2014 23:35:46 GMT+0000 (UTC)] DEBUG Message '[object Object]' matched regex //^[@]?hubot[:,]?\s*(?:PING$)/i/
[Thu May 08 2014 23:35:46 GMT+0000 (UTC)] DEBUG Sending to hubot@conference.host: PONG
[Thu May 08 2014 23:35:46 GMT+0000 (UTC)] DEBUG Received message: PONG in room: hubot@conference.host, from: hubot
[Thu May 08 2014 23:35:58 GMT+0000 (UTC)] DEBUG Unavailability received for user123
[Thu May 08 2014 23:35:58 GMT+0000 (UTC)] WARNING @userForId() is going to be deprecated in 3.0.0 use @robot.brain.userForId()
[Thu May 08 2014 23:36:09 GMT+0000 (UTC)] DEBUG Received message: hubot ping in room: user123@host, from: Spark 2.6.3
[Thu May 08 2014 23:36:09 GMT+0000 (UTC)] WARNING @userForId() is going to be deprecated in 3.0.0 use @robot.brain.userForId()
[Thu May 08 2014 23:36:09 GMT+0000 (UTC)] DEBUG Message '[object Object]' matched regex //^[@]?hubot[:,]?\s*(?:PING$)/i/
[Thu May 08 2014 23:36:09 GMT+0000 (UTC)] DEBUG Sending to user123@host: PONG
Responds on Chat room, but not DM, but the debug mode says it did send it out: