Some time ago I learned about TheHerdlocker.com from a post on ResearchBuzz. Since then, it's grown a bit, and I've been receiving useful weekly updates to a few hashtags I like to follow on the Twitter.
In a nutshell, rather than you creating a column within Tweetdeck to collect all mentions of a given hashtag, TheHerdLocker monitors a hashtag and then sends you a weekly email listing the top content using that hashtag over the past week. They claim by filtering out retweets, duplicates and spam, they knock out about 88% of what would be considered noise on a given hashtag. You can't, at this time, simply provide a hashtag to monitor; you have to pick from amongst the ones that are already being monitored. I don't know if that feature is in the works, but I do know that I've emailed the developer three times and gotten three hashtags added to the list right away, so if you don't see one you're interested in, just ask.
I'm currently monitoring these hashtags:
And here's what one of the actual emails you'll receive looks like.
It occurs to me that that is also a good way to keep a finger on a pulse within Twitter w/o ever even needed to visit the site, or even have an account!
Good stuff! No kickback, just a happy user :-) Check it out.