1 or several topics per domain?

Should I have distinct sites under a single domain?

[4thePegeh]

Is there any advantage to placing under a single domain several projects. For example, if I am interested in creating four sites: one on dogs, one on hockey, one on massage, one on stereo equipment would there be any reason to put them all under a single domain?

Ex.

cooldomainname.com/dogs/index.html

cooldomainname.com/hockey/index.html
cooldomainname.com/massage/index.html
cooldomainname.com/stereo/index.html

I realize there would be difficulties should I ever wish to sell one of them.

Would it confuse the search engines or affect the ranking of particular pages if the domain had subsections entirely unrelated to the topic of the page? for example, if the hockey site has 100 content pages each targetting a different hockey related keyword combination, would the search engine rankings of those pages be adversely affected because the main domain also hosts 70 pages about stereos written to target specific search terms relating to stereos? Do the engines get confused by an assumption that a site should be about a single topic?

I didn't find a thread on this, but if one exists, please feel welcome to add a link to it in reply.

[webboy1]

From experience of traffic percentages to different parts of sites, I would suggest (if you were going down this route) that you'd have to be very clever with your main url index page (e.g. cooldomainname.com/index.html). It's this page that will, by far, receive most of the traffic.

One of the big things thats spoken about in SEO is relevance. You ultimately still want people to read the content you offer, so focusing solely on making 4 different sections perform well on the engines is probably going to have a negative impact on the feel of the site.

I would suggest not running 4 sites about compeltely different topics under one URL. It depends what your intention is for them, but I suspect you'd be able to perform much better in SE's if each site was under its own relevant URL. Even the likes of Virgin, with all the various brands and business units they offer, have separate domains for all.

Hope this helps.

[4thePegeh]

Thank you.