If you are not at South By Southwest, your Twitter timeline will remind you this all the time.
If you do not want to see all those #SXSW tweets, then the Calloway extension is just for you
After you download and install the Calloway extension, and you enable it from the Options window you will not see any tweets containing phrases such as "sxsw", or "SXSW", or "SxSW".