There's no inherent limit on the length of a web page, and the mark-up approach will accommodate any amount of content on one page, long or short -- that's a major advantage over older media which are limited either in time or physical space.
Upside
A. Easy on spiders, browsers, and maintenance resources.
B. Message is not likely to be overwhelmed by the setting.
Downside
A. Potential for blocky, graceless pages
B. "Visual brand" may be difficult to communicate
2. Design centered (Ex: Oracle.com)
People who were accustomed to print design were very frustrated by early HTML.
They wanted to "print" on the screen in the same way that they could
print on paper. They wanted the absolute control that a press gives them.
The end result can be quite elegant. It may also be very hard to handle cross-browser, cross-platform and cross-device, as well as making some extreme demands on bandwidth.
Maintenance can also be a real grizzly bear -- and here's the biggest challenge. At its most extreme, when the entire page is forced to fit in one screen with no scrolling, the communication may be sacrificed for sake of appearance. If there's one downfall to much of today's marketing in EVERY medium, it's that advertising often trades clear communication for superficial appearance. But when this approach succeeds, these print-centric pages are glorious to behold.
Upside
A. Visual brand is directly communicated
B. Easy to relate to for those who don't "get" the web
Downside
A. Complex code is hard on spiders, browsers, bandwidth and maintenance
B. Message can be overwhelmed by the setting.
3. APPLICATION centered (Ex: Expedia.com)
One of the big advantages of a web page is its interactivity. Where would the
travel or finance industries be on the web without giving their visitors some
very nifty, interactive resources? But there are some pitfalls here. A web page
is not a software program, in that people will not usually invest a lot of learning
time. If general visitors must learn too many idiosyncrasies for a given web
page, they're not likely to hang around.
So the IT crew may develop a nifty application, but if they try to create the interface in a way that diverges too far from the standards of other web pages, they'll just confuse the user.
In fact, many times the application-centered web site seems to WANT to impress the user with the complexity of the app they've created, rather than making the information delivery as painless and transparent as possible.
Upside
A. Convenient access to dynamic information
B. "WOW" factor.
Downside
A. Complex code may confound spiders, browsers
B. Interfaces tend toward the non-standard, hard to learn