Question: If I have a site with numerous subcategories would it be better to have one domain with each subcategory linking off it, or a domain for each subcategory?

For example, if it's a sports news site, it might be something like:

```
sportsnews.com
sportsnews.com/football-news
sportsnews.com/cricket-news
sportsnews.com/tennis-news

```

etc.

The idea would be that there's an overall common layout to the sites, but the content and theming is different. 

The alternative approach would be something along the lines of:

```
sportsnews.com
footballnews.com
cricketnews.com
tennisnews.com

```

From an SEO point of view, is it best to have the one site with the rest linking off it so all the links to it are driving up the page rank collectively, or would it be best to have separate domains so that the domain, meta, title and description of each individual site all match up to the expected search keyword of `(sport name) news`?

If the latter approach were chosen, would linking to the individual domains from the primary one then be detrimental to the overall network of sites?

**Edit: Please note that sports is just an example. You can assume that although the subcategories are related 95% of users will not be interested in any others than the one they searched for.**

Answer: 
What's going to be:

1) better for your users?

If spreading it out over several domains will make the content easier for your users to navigate and use then take that route. If putting it all in one place will do that, then take that route. You want to make sure you don't lose sight of the bigger picture which is the user experience. The better it is the more likely you will gain popularity (i.e. get more traffic which one would assume is your primary goal) and increase the likelihood that you will gain natural and hopefully valuable incoming links from other webmasters who like your site. Focusing on the user is much more important, and better for SEO, then focusing on the search engines.

2) easier for you to maintain?

On site SEO obviously is important and you want to maximize it since it is all that is in your control. But don't make your site a beast to maintain just for SEO's sake. A site that is difficult to maintain eventually gets neglected. Maybe not at first and maybe only gradually over time. But it does happen and results in a degraded user experience. You want to make sure your site is easy to maintain to keep the user experience at its best. If spreading the content out over multiple domains doesn't make your life any more difficult then it may be worth doing for the advantages listed above. But usually there is overhead with running multiple sites so it may not be worth the hassle.

I personally would keep it all on one domain. It's all related content and it is likely that users will seek more then one sport out when visiting your site. Keeping them in one site is less confusing. You can do plenty with URLs and page titles, etc, to maximize your SEO without the need to get separate domains for each section.
Would it not be best to have something like

```
sportsnews.com
sportsnews.com/football
sportsnews.com/cricket
sportsnews.com/tennis

```