Tagstr's UI, with special messages in the user feed. It was important to continually improve and iterate, giving the user the opportunity to provide feedback. 
Tagstr's UI, showing the user 'Interests' view. Users can personalise their interests and assign hashtags.
Tagstr's UI, showing relevant tags nearby that you might be interested in. All personalised based on your feed, with location data stored when photos are taken/uploaded to Tagstr.