Lots of people posted tangentially related topics in threads (what's this worth, how old is this, where can i find/sell my x), I don't really see the harm in having them there. Now that guest posts are not allowed the issue has decreased tremendously. They are legitimate posts and not spam, so it would be inappropriate to delete them.
Perhaps Michael could create a separate forum or sticky for those tangentially related valuation/date/info posts to be moved into to decrease the fluff posted in the threads.
I don't see any value in going back and purging old threads either way however.
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