I've got several ideas for website content and a single domain, but each type of content is not really related to the other. Would I be better off partitioning each different topic into its own subdomain so as to keep the traffic to each site focused? Or would it be better to keep it all under a single domain so that one site will receive the aggregate of all traffic for all topics?
I dont think it makes much of a difference. I would prefer 1 domain. After all SE index individual pages and total sites.