For quite a while I've held the view that most current approaches to Web search are fundamentally flawed, because the best way to find something is not to lose it in the first place. But as the companies invested in search gradually get smarter in their use of person- and (to a lesser extent) thing-oriented data, rather than just word association (football) search results seem increasingly more focused. Google's approach in particular has grown increasingly like the model put forward in the Semantic Web initiative. Recently with G+ we see a big push to capture and exploit data associated with personal profiles (the FOAF domain) and brands (the GoodRelations domain, although maybe there's a role for an additional brand- rather than product-oriented vocab). With Rich Snippets and Schema.org there's a direct use of semweb technology (in a slightly mangled form - One True Ontology is a well-known antipattern to anyone that bothers to look at the literature).
In fact the "Your World" part of Search plus Your World (SPYW) can be seen as a reinvention of the most important part of Semantic Web technology, that of giving everything of significance a URL: people, places, things, concepts. Given that, you can start describing and leveraging relationships between those resources. To use a phrase I think originated around microformats, it's lower-case semantic web. Ok, behind the quality glitz of G+ profiles and pages this seems to have been done in a rather sloppy, ad hoc fashion, but that in itself is fine - whatever it takes. But where Google get it very wrong is by putting themselves at the heart of their system. Not only is semantic in lower-case, so is web. If you do a search with SPYW enabled, you're pointed straight back into the Google Empire. They are making themselves gatekeepers of the Web. Although there aren't any concrete entry barriers to this walled garden, by only signposting Google's footpaths in search results it's creating a system with the same characteristics as say AOL around 2000. From Google search being a vital accessory on the open Web, it's increasingly becoming a portal.
There is already a visible cost in practice to Google's echo chamber - if you want to re-find something one of your colleagues said the other day, sure SPYW is helpful. But if you're trying to do some original research, you don't want to be searching with Your World blinkers on - an engine without those preconceptions such as DuckDuckGo will be more useful
This strategy I'd assert is doomed to failure for the same reason AOL's walled garden collapsed, to use another phrase I like to repeat, because no matter how big any single entity becomes, the rest of the Web will always be bigger. The focus on the user/Don't Be Evil thing is absolutely right to highlight the value of non-Google resources, although it does fall short by suggesting that the rest of the Web is just a handful of other companies [G+ link] i.e. Twitter, Facebook etc. Google's own long-term survival as a market leader is absolutely dependent on their respect of the Web at large.
So what should Google do? Re-read Steve Yegge's awesome rant [G+ link] for starters. Especially the bits about Platforms. G+ and Your World should be considered in this context - as a semantic (any case) Web (upper case) Platform. For example, while Google's pages appear to be aimed at providing the canonical URLs for concepts (...lower-case). But there's already an excellent source of such URLs : Wikipedia. In itself Wikipedia only provides URLs of documents who's primary topic is the thing in question, but dbPedia is a well-established mapping based on best practices from thing identifiers to Wikipedia pages (e.g. <http://dbpedia.org/resource/Berlin> foaf:isPrimaryTopicOf <http://en.wikipedia.org/wiki/Berlin> . ). If a handful of students from obscure north-European universities (heh, sorry, just for the sake of contrast), with a little community support can create and maintain - give the world - a service supporting all the concepts/things covered by Wikipedia, imagine what the mighty Google could achieve...
To give a little example in the context of Personal Profiles, if I publish my definitive personal profile on my own domain (note Google already understands all the elements of this) then for queries for which "me" is the appropriate response, that page should be the first hit, not my G+ profile.
Another factor in the walled nature of G+ is the limited API. I'm sure features will be added to this in the near future, but I hope (probably unrealistically) they will use proper standards and follow known best practices. Going further into over-optimistic territory, I'll quote Tom Gruber (in an interview talking about how Siri works) :
A site that exposes RDF usually has an API that is easy to deal with, which makes our life easier. For instance, we use geonames.org as one of our geospatial information sources. It is a full-on Semantic Web endpoint, and that makes it easy to deal with. The more the API declares its data model, the more automated we can make our coupling to it.
What should we (as users and components of the Web) do? Well, basically what we're already doing...but trying not to be distracted by shiny things and keeping an eye on the long term - standards are good. When we publish data on the Web we need to consider the quality of the data first (i.e. make it 5 Star), seeing it as purely Google-fodder is missing the point.
Comments please [Google+ link, the irony is not lost on me :)]