As far as getting your sites ranked well in the search engines, how significant is it to have multiple pages under a more generic domain? Like, if I wanted to have "joeblow.com" as my root domain with a number of different pages focusing on various different niches and products, would that seriously hurt my chances of getting any of the pages near the top of the SERP's compared to having separate relevant domain titles for each product or topic?
Exact domains are still easier to rank than generic ones. But it's getting really hard to get them as there are a lot of people out there who are making a living from buying those and they started years ago Personally - I try to get one for a new niche but don't bother for subsites or product groups. It's just not worth it. Over time you will still be able to rank generic pages, too.
A common way to do this is to add subdomains. keyword.mydomain.com By making your small niche keyord sites authorities, your main domain has juice as well. Your main domain points to your subdomain niche sites and they have links to the main domain. It creates its own internal link wheel. Your subdomain sites are laser targeted so search engines like them and visitors interact. By making these sites good your main domain gains authority. Your sub domains provide your content, your main domain provides your JUICE. As you grow so does your authority and ability to rank higher faster. Hope that makes sense. ODA