Lead

Successful completion of a web-based task, as defined by whoever is tracking for the conversion. Typical conversions are things like signing up for a newsletter, the sale of a particular product, or clicking on an ad.

Refers to both the front end (what the user sees on a website) and back end (processing, data storage, etc.) of a website. Full stack developers are those who work in design environments for both front- and back-end projects.

A measurement of how involved your audience is, either holistically or for an individual ad or ad campaign. Depending on the marketing channel and ad being analyzed, a variety of metrics can be considered to determine engagement rate. It is used most frequently to analyze social media marketing.