I've set up a few activities on our site, one that targets returning customers and another that targets new visitors. The number of entrants seems very low. (Only 1k over the course of a week or two). 

I'm concerned that this means that the tracking is not setup correctly. Since both of these are experiments on our landing page/visible on many different pages, I would expect the number of entrants to track closely to the total number of sessions that we see from Google Analytics.