With your version, I think you're going to run into some major performance issues down the road.
I've developed the system linked before for my CMS and haven't had a problem in terms of performance because the MSSQL Server index is built well. It would be nice if this could be added for Snitz or at least a retro-tagging feature that could be run monthly. I can no longer use search and I have mssql server. Tagging could help that.
Even after developing this, I recommend that you build a static html file on a daily or weekly basis with your tag cloud and call that page instead and you could even go with your version because if you're only going to run it once a day it really won't matter how inefficient it is.<