I have a read (a little) about the importance of site maps - but can someone tell me how much importance does Google place on them?
The main purpose is to provide a means for quicker discovery of new and updated content. I find that since I started using sitemaps, my number of indexed pages has gone up. Also remember, google isn't the only search engine that can use sitemaps. You can submit sitemaps to ask, live, and yahoo also.
That's right. The sitemaps help in facilitating better crawling by the search engines and it is another way to inform the bots about when and how frequently your sites are refreshed. So, it is better to have one than none.
The main purpose of the sitemap xml is to let google know about all your pages . Let's just say you have pages , but no internal links to it , google probably won't find out about it . That's why the xml sitemap for.
As stated before I've found using sitemaps gets my new pages indexed wayyy faster than before when I didn't use them. Also seems like it gets crawled more often.
It is important for Google. It is important for your sites if you have a site with many pages. It helps your site to be crawl more in a timely fashion. Thus, improves your pages in SERP.
Say you are traveling to a place, it would be easy for you if the city officials places a road map on the street . Similarly , a sitemap aids the search engine crawlers to find out the inner pages and posts of your site .
It allows the search engines to know about (and to find) your new content quickly. Whatever the size of your site this can help a lot in your SEO efforts. If you have a large site that's frequently updated it's even more important.