Discussion here is a flow of messages (statuses) with some hash tag. Mashup lets users add a special status for the own timeline during the first visit. It is like check-in. This check-in record contains hash tag for the discussion. So, user can switch to search right with one click right from your new post. Additionally, user's timeline will keep check-in record (read - description to hashtag), so it is easy to return back to that discussion. For subsequent visits mashup simply redirects user to Twitter search page for the given hash tag.
You can set your own parameters for the discussion. Basic URL proceeds the following parameters:
tag - tag for discussion
title - explanation for your discussion
checkin - check-in message to be published in user's timeline
via - Optional. Twitter's account to follow for the check-in message
For example: http://twicus.linkstore.ru?tag=mytag
Such way you can add links to your site/blog: 'Discuss in Twitter'
How it could be used? For example, second screen application for social TV.