Hi
Yes it is absolutely necessary to use specific keywords for each page. general rule of thumb is 1 primary and 2-3 secondary key word phrases.Your websites success of failure depends on how you use keywords on your site, on pages, headings, titles, content, images, internal / external links.Check out Marvins DotNetNuke SEO 101 to learn how to build your link strategy then use our DotNetNuke 101: DNN 4.9.x User Guides and Tutorials to quickly build your site. There are step by step SEO instructions in the user guide.Have a Good Day.