If you catch a glimpse of this feature in the wild, you'll see a slim strip of avatars on a user's profile right above the grid of people that user follows. The headline above this reads, "You both follow."
You can also choose to click the link below this avatar-strip snapshot to see all of the people you and the other Twitter user both follow. We're thinking this will make Twitter a lot more interesting for stalker-types, as well.
Overall, this new feature is a quick reference tool that shows deeper connections in the social media grid, and it's a simple addition that makes Twitter seem less like a one-way communication tool and more like a robust, legitimate social network.
Also, it doesn't take a rocket scientist to deduce that this feature is ever so similar to Facebook's featuring mutual friends when you visit the profile of one of your current Facebook friends. But we won't be so petty as to accuse Twitter of stealing the feature; we might, however, say that the mutual friends snapshot is sufficient weregild for Twitter features that Facebook has appropriated over the years.
Will this feature, if and when it's rolled out to all users, make it easier for you to keep track of who's who -- and who you might actually know in some meaningful context -- on Twitter?
[hat tip: dacort]