I think that there are a number of reasons but I believe the ultimate goal is usage, and by that I mean page views, time spent on site and number of users. Site owners rely on active communities to generate traffic, retain users for longer times and in some cases generate content; all in order to, hopefully, generate revenues. But what some of these site owners don't realize is that they might not need all that to make their site successful. Moreover they probably don't realize some of the potential risks associated with interactive communities.
So does every site need an interactive community? I think I've made it clear that my answer is no. There are a few distinct types of sites, that I can think of, that do not need any kind of interactive community.
- Banking sites; those sites that are used for online banking and/or as banking portals. This does not include sites like paypal, google checkout, etc.
- "Transactional"sites; I use the term transactional very loosely, but this group basically covers sites where people place orders for certain things like pizza. It also includes sites where people can pay for products or services (i.e. AT&T) .
- Corporate sites; Corporate sites are usually exclusively informational. It is important to differentiate corporate site from micro-sites or sub-portals that may have community components to them.
It is also important to note that the types of sites I listed does not mean these companies shouldn't have interactive community initiatives. What I mean is that they do not need it within the specific site (i.e. corporate site). Companies can certainly have other sub-portals, micro-sites or twitter/facebook accounts... but maybe they should try to keep certain areas (properties) "clean" if you know what I mean.