It is a tool that allows users to submit multiple sitemaps to search engines automatically. This is a great app for SEO (Search Engine Optimization) enthusiasts or anyone that is tired of having to manually resubmit their sitemap to search engines just because something was changed. How it works is by sending a message to a search engines “ping tool” to tell it to crawl the website again. Currently there are only two major independent search engines (which is pretty much 2 out of 3) that still support sitemap pinging. The third major independent search engine (Ask.com or AskJeeves.com) shut down their ping tool last month because they “now utilize a crawling method of adding new content to our search index”. Back in November 2011, Yahoo! also shut down their ping tool (aka Site Explorer) and they are no longer a independent search engine because their search results are now powered by Bing.