A Key Performance Indicator(KPI) or Key Performance Metric(KPM) is, simply put, anything that a business finds important and valuable to track. This might include:
- Clickthroughs from paid advertising
- Clickthroughs on organic listings
- Number of quotation requests submit over a particular time period
- Activity related to a particular product launch or advertising campaign
Website traffic is not generally a very useful indicator. It is up to the marketing department or management to determine what KPIs are important.