Just suppose I have a number of websites. What would happen if I included a link to each of the others in their respective sitemaps?

The sites would be linked together.

I'm not really sure what it is you're wanting to know. Is your question in regards to how it will affect search engines? Or are you asking something different.

Happy to try to answer, but not entirely sure I understand the question.

Nothing will happen. It's good to link all your site together. It's even better to link with other site to make your site more friendly to the Search Engines. I think so...

Not too much help. You'd better set links between your websites rather than setting in sitemap files. The main function of sitemap is to guide spiders crawl your internal pages.

It will help Search Engines bots to crawl your site easily.

Originally Posted by hhheng

Not too much help. You'd better set links between your websites rather than setting in sitemap files. The main function of sitemap is to guide spiders crawl your internal pages.

same!