Share sheets are great. Apps can add themselves as either apps (coloured icon) or activities (black and white icons). But I noticed that developers don't know how to choose between the two. 1password is an activity: fill out a form. ok. Wunderlist and Things are also activities. Maybe, not sure. Pocket and Evernote are apps. Maybe, also not sure. I fail to see the difference between the last two groups. What's the difference between adding a URL to pocket or adding a task to your todo manager?