In the world of Hai:OK, @ replies should work now, with a new format: You have to surround the name with @ and @, instead of using the old @"Name" format. The version with the quotes caused parsing errors a lot, and the new format is a little quicker to type. The documentation's already been updated.
So, to ping someone, type @ followed by their name, and end it with another @.
Also, you can now drag-and-drop images into room descriptions when creating them. Enjoy!
Photo credit: www.flickr.com/photos/goulp-ru/23049471810/