I have a Social Networking website, where I offer users their own subdomains. But Google is not aware of all the new members joining in my website and hence all the suddomains in my website. Is there a way to submit Subdomains through Webmasters to Google under my www .domainname. com account. Thanks.
If you are asking if you can mix URLs of domain/subdomains in XML sitemap file, the answer is no. Not following the XML sitemaps protocol as defined by the search engines, e.g. Google.