Starting from version 2.1.0, Talk lets you search discussions by text and commenters.

Use the standard Confluence Search field on the top bar to enter your query.

The search queries syntax is the following:

QuerySearch byExample
talk:"some text"Text in discussions

talk:release

talk:"do that ASAP"

talk:"User Name"Users who left Talk comments (search by login name or full name)

talk:"Alex Smith"

talk:Alex

Make sure to include your query in double quotes, if it contains spaces. Search by commenter also works only for a part of a name.