One of the big selling points/innovations of Google Plus is its inclusion of circles. These are basically lists that allow you to organize your contacts into custom lists which are used to control who can see a particular post. Circles are great for controlling privacy (you can post pictures of last night’s party to your “Bar Friends” circle and not have to worry about your grandmother seeing them) and for controlling the signal-to-noise ratio of your news feed (people who you don’t know or who post exclusively about what they had for dinner go into the “Don’t Care” circle that you never bother to check), but aren’t very useful for targeting posts to people who you don’t know very well (or at all).
The big problem with circles as they currently exist is that they only work if the user knows what circles his contacts want to be in. This is fairly easy for close friends (Zed goes into the movie and politics circles, but since he doesn’t game, I leave him out of the RPG circle), but much more difficult when it comes to casual acquaintances (I know Ferndando is a gamer, but have no idea if his musical tastes are anything like mine). And then there are the people you don’t know, which is especially problematic if you’re a writer, musician, politician, business owner, or other public or semi-public figure (Is this guy a QAGS fan, someone who likes my political rants in the local alternative rag, or somebody I went to college with and don’t remember?).
From the poster’s perspective, a circle becomes less useful if you’re not sure that you’ve got the right people in it. When it comes to important (at least in your estimation) news, you’re more likely to just ignore circles entirely and post publicly so you don’t miss anyone, which sort of defeats the whole purpose of having circles in the first place. On the reader end of things, getting put in the wrong circle means you’re not getting the content you want and clogs up your news feed with stuff you could care less about. If a poster is consistently posting things you don’t care about (either due to overuse of public posts or having put you in the wrong circle), eventually you’re going to unsubscribe from their feed or stick them in your own “Don’t Care” circle.
Right now, the only way to know who wants to be in a particular circle is to ask them what circles they want to be in. Unfortunately, there’s no really efficient way to do that. If you use private messages, you have to do it for each new contact and send new messages to everyone if you start a new circle. If you use posts, you have to regularly announce the circle so that new followers can opt in. In both cases, you then have to manually add everyone who responds.
There’s an easy fix for this, which I’m sure somebody has already suggested but I’m going to chime in about anyway: give users the option of making circles public and subscribable. Whenever a user decides to follow someone new, give them a list of that person’s public circles and let them select which ones they want to subscribe to. To make it easy for subscribers to add or remove subscriptions later, list every user’s public groups on their profile page along with a link that allows people to subscribe or unsubscribe.
In addition to allowing posters (especially those who use their profiles to promote themselves or their business) to more effectively target their posts, subscription circles would be very useful in allowing readers to organize their feeds. For example, I might to care what my favorite author has to say about writing and what books he’s got coming out, but not give a damn about his favorite sports team. Allowing me to subscribe to his “writing” circle and disregard his “da Bears” circle allows me to cut out the noise without losing the content I want. With a few additional tweaks, opt-in circles could be used to provide a functionality similar to Facebook’s groups or fan pages, which will be important when Google Plus opens up the doors to businesses and other organizations.