Some Blogger blog owners don't know how to setup a sitemap, for their blog.
Setting up the sitemap, for a website, is a major process - and takes time. Every time you add a page to a website, the sitemap has to be updated - or how do your readers find the new page?
Alternatively, you can use a sitemap builder service, which builds the sitemap. This gives you a file, hosted by the sitemap builder service. Will the sitemap builder service be in business next week?
In either case, you take your sitemap file, and upload it to the blog. Every time you add a page, you update the sitemap, then you upload the updated sitemap. Every time - or the new page remains unindexed, until you do.
(Update 2014/11/04): Blogger is now providing an automatically generated, dedicated sitemap, to replace the newsfeed sourced sitemap - and an automatic "robots.txt" update. There is no need for a custom sitemap - nor to update "robots.txt".
With a Blogger blog, you designate the sitemap, using Google Webmaster Tools, referencing the URL of the posts newsfeed.
You can substitute any custom sitemap, if you wish, but this will be at your own risk - and you can develop your own installation instructions.
Once done with the Webmaster Tools sitemap wizard, you are free to work on the visible parts of the blog. Every time you publish a new post, the post is updated into the newsfeed, and becomes part of the sitemap.
The next time a search engine bot hits the blog, it picks up the new sitemap - and indexes the new post.
Combine the automatically and immediately updated sitemap, with more time spent updating the blog, and you get happier readers, and better search engine reputation. That's a win - win.
If your blog gets very large, you can add a new sitemap segment - at your convenience - for every 500 posts.
Why spend time manually updating a sitemap, with every new post (and worry about a file, hosted by someone who may or may not stay in business)? Use the posts newsfeed (hosted by Google), and work on the blog content.
An Important Update
If you did not use a Blogger / Google account when you Followed this blog, years ago, you are probably not Following now . During the past...