Many try to compare Facebook with Google+, and often they conclude that Facebook har more friends, so they will not switch to Google+.
However, Google+ should not be analyzed as a Facebook killer. It isn't. Facebook has a huge head start, and even though Google+ has grown extremely fast, most current users were already gmail users. For those that do not have Google accounts, Google+ is not as obvious.
It is not a good idea to compare two systems using a one-dimensional good/bad scale, there is much more to comparisons than that. Initially, Facebook really annoyed me, because each country in Europe had it's own network, and you could only be part of one network. Then, they removed that feature, and few people really noticed. Then they added groups, then they hid them well, then they added friend lists, then they added "Top news" and so on. The core of Facebook, that has persisted all the way, is a friend list and posts, and the ability to keep the profile 100% out of search engines.
Google+ has a different approach. The core seems to be the friend list and circles, but the friend list can include people that do not acknowledge the friendship. The profile contains part that cannot be hidden from the public, such as the name and photo. So, the list of friends works differently and the circles are part of the core user experience. By doing that, Google+ will be able to do other things than what Facebook can do, and generate a different user experience. It's like comparing a bird with a human - both have skills that the others have not, but some skills overlap.
There is no doubt that Google will integrate their services further. The Google+ account is used almost everywhere, from blogs to email, and circles are now supported by Picasaweb, Google Latitude, Huddle and Hangout, but will probably also come to Google Docs, and maybe we will see Google Groups reinvented as "Shared circles". So, instead of sending emails to the scout parents, you can now post on Google+, and some will receive the messages there, some will receive it by e-mail. Those that have Google+ accounts will be able to discuss the message online, immediately, without spamming people's mail boxes. And you can keep it totally separated from your Golf club while still handling messages from both in the same place.
So, what does Google+ kill? Well, currently, not much. But it will improve sharing of information, especially among people that already have Google accounts. But because the fundamental mechanisms are more advanced than on Facebook, more can be built on it. Facebook will continue to have the advantage of size for quite some time, which should technically put it in the position of being able to compete well, but because of Facebook's reputation, many may not perceive it as a serious way to share important stuff.
Will people have time for Google+? I believe that they will, because it can be a more efficient way of spending time, than looking into e-mails and various other online forums.