the meta tags you mentioned above are html codes that describe what your web site is all about. meta tags identify the author (site creator), generator (the program which was used to create the site like frontpage, dreamweaver), classification (type of html document definition), and some tags like keywords, allow you to include certain words that can be related to your site.but as far as Search Engine Optimization (SEO) is concerned, it will involve more than including meta tags to your web site

SEO is the art of 'driving' traffic to your site. though there are no sure fire formula to SEO heaven, some argue that the site's structure has a lot to do with it. Here questions like 'is your site fully web crawler friendly?' comes into the picture. some search engines also put into consideration the other sites linking to your page. others emphasize the infromation posted on your site (strategically and statistically placing keywords, though some find this a bad practice).hope this helps
