It is possible to search for Ideas by Idea Comments or Idea Votes fields.
To search through Idea Comments field use '=' operator and following functions:
commentedInPortalBy()
commentsCount("", "")
internalCommentBy()
internalCommentsCount("", "")
publicCommentsCount("", "")
withAuthorsCommentedBy()
withAuthorsCommentsCount("", "")
Idea Votes field
Valid operators: >, >=, =, !=, <=, <, is, is not.
Available functions:
downVotes("", "")
totalVotes("", "")
upVotes("", "")
votedIdeasByUser()