6. The method of claim 1 , wherein: the submitted query is submitted by a particular user having a particular username that corresponds to a particular activity level with respect to a network-based system; and the determining of the strength score is based on the particular username corresponding to the particular activity level.
7. The method of claim 6 , wherein: a further query among the plurality of submitted queries is submitted by a further user among the plurality of users, the further user having a further username that corresponds to a different activity level; and the determining of the strength score includes determining that a pertinence of the submitted query to the theme is greater than a further pertinence of the further query to the theme.