One important difference between the Recent Content and Recent Activity widgets is how they present information: Recent Content is more content-focused, while Recent Activity is more people-focused.
When you're scanning the Recent Content widget, you're likely first noticing the titles of content -- documents, discussions and replies, blog posts, and so on. Titles tend to stand out on the left side of the widget, with people's names and small avatars on the right.
The Recent Activity widget draws your attention to the people behind the activity -- largely because their avatars and names are displayed in a larger size at the left. Also, the activity widget captures a broader range of activity, making it a more complete snapshot of what people are doing (rather than what content is doing). For example, in versions featuring bookmarks, a person's new bookmark will appear in Recent Activity, but not Recent Content.
As for popularity, that's calculated based on how much attention the content is receiving and how much time has passed since the attention was received. Popularity "points" are awarded for things like comments, changes, and views that content receives, but those points decrease as time passes since they were awarded. For example, if your document received three comments and 15 views and was edited once on the day you published it, it would be more popular than a document that got 10 views, no comments and no edits on the same day. However, after four days of no activity -- with its points decreasing each day -- your document would be less popular than a document published today that received the same attention yours got four days ago.
Thanks, That helps but need some additional detail.
If I have a combination of those widgets on the same space is there any things that need to be considered. Not sure if it "likes" having both on one space?
We also have content in different subcommunities and want to share comonly the results across the space and sub-community.
There's no technical problem with having both widgets on the same page. They go together just fine.
I don't think I understand your second concern. If you're saying that you want to use the widgets on subcommunities as well, there's certainly no technical problem with that either. If you want to have a widget in one community's overview list content from that community's sub-communities, then you can have the Recent Content widget do that.