The selective #hashtag is a good idea. We’re currently testing if a filter to “exclude” tweets is all that is needed. Twitter feeds are currently filtered for the “@” symbol so @Replies don’t flow into Real-Time Ads. But a client could also set up “;)” as a filter and then use to exclude their non-marketing tweets. In my analysis of businesses that twitter, non-marketing tweets were rare. So implementing a unique hashtag seemed like adding a task. Of course, our beta testers will let us know what is best!