I think the most serious concern is how Google promotes its own offerings above more popular competitors in the search results section. For example, do a search for "finance" and Google Finance is shown above Yahoo! finance, even though Yahoo! finance is better by most measures, and far more popular (see http://www.businessinsider.com/google-finance-yahoo-finance-... )
If you rely on Google to drive traffic, but also compete with Google, that puts you in a difficult spot.
Consumers ought to be annoyed too. Google has historically does a good job distinguishing between links that are artificially promoted (ads) and algorithmic rankings. But Google is artificially promoting their own offerings and presenting them as if they're a result of the algorithm.
This seems like a bad strategy. It has the potential to shake user confidence in Google's impartiality and link quality, annoy site maintainers, and drive away advertisers.
I'm not convinced that Google moves it's own results up as part of the organic search results. Bing puts Google Finance first before Yahoo Finance as well. Regardless of it's popularity, its position may simply because of other signals in the ranking algorithm.
Google freely admits to putting their own links first. Here's what Marissa Mayer said in 2007:
We didn't actually have Google Finance until about a year ago. Up until then we were ordering the links based on various published metrics... We had the five top finance sites in their order of their popularity listed there. So we rolled out Google Finance, we put the Google link first.
Your observation regarding Bing is quite interesting. Your theory may very well be right, but there's a hilarious alternative:
It's known that Microsoft uses Google's rankings (see http://googleblog.blogspot.com/2011/02/microsofts-bing-uses-... ). This would then propagate onto Yahoo, which uses Bing's engine, which means that Yahoo is told their own site is less popular. But Yahoo puts their site first, which may mean they're artificially boosting its ranking, under the guidance of you know who!
So 2012 Marissa Mayer may be artificially boosting Yahoo's rank to defeat 2007's Marissa Mayer's artificial boost of Google's rank. Ha!
Mayer's answer actually starts at 44:34 and gives the proper context: she's talking about the order of links in the OneBox (the area at the top that shows the current stock price and a plot), not the order of links in the main results. Danny Sullivan wrote a long post about this: