I am the first to emphasize the importance of appealing and nice look and feel of the web site. The visual impression is a critical criteria for making the first impression and setting the inspiring mode during your visit to the web site - like a background music you enjoy and inhale...Appealing design is critical.
And of course GUI is key - to enhance the efficiency and ease the use of the underlying logical functionalitIes/application - and make the navigation as intuitive and seamless as possible. Clever GUI design leads to high level of interactions which is engaging, entertaining and consequently very effective communication.
However - said all this - the real key of the matter and proof of the pudding is in the content !! CONTENT is everything. Content is all about bringing substance to the surface - about having a story and a message highly relevant to your audience. The clue is to transform content into entertaining and engaging STORYTELLING. Highly skilled use of multimedia tools such as high quality images, high quality video (very well directed and edited), well prepared text, super relevant music contributing to set the right atmosphere etc. This is where you by crawling around the www can really separate successful and effective interactive communication from mediocre monologues and super boring attempts to attract audience.
To succeed with ONLINE communication you really have to take this seriously and make sure you bring together the right set of skills and expertise to make this possible. Some environments are doing this - but far too many fail to do this right.
Am I right ? Take a walk on the wild side !