I just want to include important and regular urls in the sitemap. Other urls are linked from those urls. Is Google going to index those urls not in sitemap, or will put them into lower prority. I just have too many urls and difficult to write sitemap for it.
of course they will index them. If the the search bots can find the url form other links, they will index them without any problem. Just make sure your site is well linked to.
Yes they sure will, the best way for them to do it is do good internal linking, so say you have a products page and a contact page instead of putting contact.html in the link page put http://www.yourlink/contact.html and google will index it faster. I recommend a sitemap though for optimial indexing, most people who have sites dont even have a robots.txt or a sitemap.xml, i harsh recommend both if you are doing seo.
So it suggests that I can I put the most important urls in the Sitemap, and let Google crawl and index the rest unimportant urls? Are those modified, frequency field necessary or beneficial for Sitemap? Is Google strictly following the xml?
Yes, robots.txt and sitemap are very basic of seo. Many cms have the function of automatic sitemap, we don't have to make it manually.
Out of interest, why would you note want to have all url's site mapped? ____________________________ resume services by itouch
It is just some random pages... and I don't have a CMS for this old site with thousands of pages, and Google seems slow indexing them.. So I am thinking of Sitemapping important pages (about 100 pages), and let Google crawl/index the rest... But fear if I miss pages in Sitemap, Google won't index them