Something that has a huge effect on a website’s development is the extent of interactivity it enables. Every website allows visitors to navigate it using links and most of the website owners enable the use of search boxes and contact forms.
However, some sites allow much more sophisticated interactions and become more or less indistinguishable from software. Facebook is as featured as any email program for instance. Adobe has online photo editing software including Adobe Photoshop Express Editor.
Think about how you want your visitors and audience to interact with your content. For example, do you want them to be able to comment or vote on their favorite pages? What about including an interactive tutorial that defines how your technology works? Do you want people to be able to connect with their loved ones and share information with them? And what about allowing people to customize and download content?
To sum up: What kind of experience do you wish your site visitors to have? And how much empower them to do?
In many website design projects, the amount and type of interaction determine the cost and complexity. Flash animation needs more specialist design skills, suppose, any site that involves gathering data from visitors will require software to be installed on the server. However, in many cases, that kind of software will require being written primarily for the site, and it can be expensive.