Activity scores are a measure of interaction with a particular idea on Solverboard. It's calculated from the amount of views & comments an idea gets.
Your Platform Manager or Innovation Manager can set a threshold at which an idea is deemed popular enough to assess. If an idea gets a lot of engagement from your users, then it's probably worth investigating further!
For now, this threshold can only be set via your platform settings, so we'll be able to do this for you, either when we get you set up initially, or on request. We'll be working on handing this over to you in a future version.
Once it reaches the threshold set, an idea's activity bar will go green, and it will be flagged to your Innovation team to suggest they review it.
You can also view an idea's activity score from the Ideaboard by hovering over a particular idea.