BigQuery is a web service from Google that is used for handling or analyzing big data. A serverless, highly scalable, and cost-effective multi-cloud data warehouse designed for business agility.
As an example, getting someone to open an email is an act of lead conversion. Then again, having them click on the call-to-action link inside that email is another lead conversion. Also, going to the landing page and filling out a registration form to read your blog content is another lead conversion. And, of course, buying your product is the ultimate goal of some if not all lead conversion.