drewp

I measured something on twitter. I have 67 followers. If you tagged a random 20% of them, how many could now look at their follower list and see a tagged user? The answer is about 20-50% of them, depending on which of my followers you tag.

The chart shows various runs of this process where the tag fraction varies from 10% to 100%. In each column, the lower + are cases where we happened to tag "unconnected" people. The upper + are cases where we tagged "connected" people, i.e. they led to a higher percent of followers seeing tagged people themselves.

There's only one way to tag 100% of my followers (hence the single + on the right), but even then, only 80.6% of them will see tagged users in their follower lists. In other words, about 20% of my followers are not followed by another one of my followers.