Everybody knows what Sitemap is. Sitemap is basically list of all pages on one site that are available to user or robot crawler. There are two types of sitemaps. One is standard html view of all pages, which help your visitors (also search engines) to find your content pages
Other type of sitemap is xml sitemap (just for search engines). These xml sitemaps are introduced by Google so site developers can publish list of their site pages and with that help crawlers to find them and index them all.
Now about importance! Having the sitemap is not guarantee that your sub pages will be crawled and what is worse even indexed (if your site is not worth enough in the eyes of the search engines e.g. Google, then Google will index your site only until certain level of depth). However ensuring that your site have sitemap will secure indexing until certain depth when your site gets value and it will show you possible errors which robots encounter while indexing your site, so you can fix them.
Basically you will have indirect seo benefits, by ensuring that pages are getting indexed.
It’s better to be ranked somewhere then nowhere. But sitemap will not add value and improve your ranking against other indexed competitors.
Best benefits of sitemaps can be seen on new sites and large sites.
This Sulumits Retsambew site is using excellent Karailiev sitemap generator, plugin for Wordpress, but there are numerous scripts and tools around the net that are intended for generating sitemaps for various static or dynamic sites.
Here are basic steps for making your site sitemap compliant.
First step is installing appropriate script for your cms. You should point script to put sitemap in the root of your site so it can be easily accessed. For example www.yoursite.com/sitemap.xml
With only that done most of the search engines will eventually find your sitemap over time, but its always good thing to mention your sitemap link somewhere on the page.
Second step is to ensure your sitemap is ok and working. Register an account at Google Webmasters Tools, add your site and add your sitemap. After few days you will start to get data about how Google is using your sitemap and any error their crawler experience.
That’s about it. Feel free to suggest or notice me for possible errors of my understanding of sitemaps.
Sitemap importance | Sulumits Retsambew
I have something more to add for sitemap - Sitemap is also important as you can easily get your site indexed in G without any more delays. Generating sitemap through some software and submitting them to G will help quite more than any other method.