The “inurl:” operator searches for specific text in the indexed URLs. You can pair “site:” with “inurl:” to find the sub-domain in the full URL. Why would you use this instead of #3? On the one hand, “inurl:” will look for the text anywhere in the URL, including the folder and page/file names. For tracking sub-domains this may not be desirable. However, “inurl:” is much more flexible than putting the sub-domain directly into the main query. You’ll see why in examples #5 and #6.