site map actually of two type one of xml site map and the other of html site map the xml sitemap for the google so that crawler index the page easily and the html is for the visitor that visits to the site
if you think that you have to promote your business for the long time and have time to promote it then you have to go with the organic seo technique and if you have money and you want that you business grow instantly then you can choose ppc pay per click but yes ppc is only for short time as you...
actually when google crawler crawl all the site and fetch the all the information then where it found image it is don't know what is this so to tell the crawler that it is the keyword relate to this in main things alt tag is used to tell google that it is the keyword and then crawler used that...
google analytics provides the information regarding the number of visitor it is of the free service of the google to the webmasters or the professionals