PeepSo streams can easily be searched for hashtags, or keywords.
The search is available on main community stream, profile stream as well as group streams if you have Groups plugin enabled.

It looks like this:

Available Options #

• Show my posts – Once clicked, user will be able to chose whether to show their own posts or not
• Magnifier icon – Once clicked the form will expand allowing the user to search for a keywords or exact match
• Hashtag icon – Once clicked the form will expand to allow user to search for hashtags