could be a savior when it comes to times that events kick off (ahem SXSW) in being able to mute particular users, apps or even hashtags on Google Chrome and supported native clients. The simple extension installs easily and has a ton of filtering abiltity. Setting and prefrences even sync across clients you install this on.
I immediately found benefit blocking such things like Foursquare checkins pushed to Twitter and a few other select hastags and variables.
You can not only filter the above, but use it in reverse to only show tweets with links (thanks to their FAQ for that tip). The developers have no ads embedded, so there is no money to be made here. They only request beer.