In Recent Activity you can see what is happening around your account, like the activity on your photos, reply to comments or reply to group invitations
Tap on the user who commented/favorited to view their photos
When you are in recent activity you can tap on the avatar of the user who commented or favorited a photo, this will display that user's photos.
Reply to comments right from the recent activity view
When you are in Recent Activity you can reply to to the comment right there, just tap on the blue arrow next to the comment.
Reply to group photo invites
In recent activity you can tap on the blue arrow next to a group invitation to reply. This will open a browser interface inside FlickStackr where you can accept or reject the invitation.