I'm no longer on Facebook, but I receive more information that is of value to me on Twitter than on Google+. It's easier for me to find new sources to follow, and easier to skim through a large number of tweets in order to find what's interesting. It's wonderful as a discovery engine, and I routinely find articles that I would not have found via news feeds.
I subscribe to just a couple of hundred people on Twitter. I don't follow anyone back simply because they have followed me and am not interested in whether those who I follow will follow me back. My own tweets consist mainly of links to my blog posts, which aren't very frequent. I don't re-tweet anything. I bookmark interesting articles on Pinboard.
Probably the value derived from any of these networks depends on our use of them. The way I use Twitter is a kind of hack, because it breaks the recommended rules of engagement. I will never get a following on Twitter, and never have "influence". But if I were to use Twitter in the way that social media experts recommend us to use it, the comments I found in the Google+ comments stream for PMCoder's article would be entirely valid: "You can't compare Twitter with G+. Twitter is used to tell other people what you are doing right at the moment." and: "It's unfair to G+ to make any comparison to Twitter I think. Twitter is like a mind-numbing stream of unconsciousness."
Google+, and other networks have the ability to overcome Twitter's inherent problems: both the ones related to "signal versus noise", and the fact that Twitter is a terrible venue for discussions. On a functional level, Google+ could easily step in and replace Facebook. It all depends on how many people come to the party. With networks, it isn't always the best ones that win. For example, Identi.ca has many advantages over Twitter and even Google+. Unlike Twitter you can follow a conversation. Unlike Google+ you can easily find an interest group to follow and participate in. Unlike either of them you can self-host a Status.net node and still hook up with people on Identi.ca and other networks.
I really hope that Google+ catches on and chips away at the popularity of Facebook and Twitter. Not because I love Google more, but simply because fragmentation will hasten the day when all of these networks are forced to conform to a single standard, as happened with email. Yesterday's Christian Science Monitor article, "Facebook IPO: Who's resisting Facebook and why" points out that even today, four out of every ten Americans are not on Facebook and, "If all those people continue to shun Facebook, the social network could become akin to a postal system that only delivers mail to houses on one side of the street. The system isn't as useful, and people aren't apt to spend as much time with it." Although there are people who will never join any of these networks, and even those who will never acquire an email address, social networks will be a lot more useful if we can reach a point when it simply won't matter which network we post to.
The technology is already there. It's only a problem of implementation.