I'm sorry...
... but just NO - Multimap was shite - it was always shite. Google maps blew everything else out of the water when it came along and (perhaps most importantly) was much, much faster.
It could be argued that many improvements made by Multimap wouldn't have happened if Google Maps hadn't come along - even Bing Maps is something of a Google Maps copy (actually, Bing Maps isn't as awful as you might expect).
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> Any new online business will pretty much stand or fall based on its
> relationship with Google
Maybe - unless the business is in China perhaps where Google isn't dominant.
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> to the extent that if you don't design it to be "Google friendly" you
> may as well pack up and go home.
Not really - Search Engine robots, including Googlebot, pretty much read web pages in the same way that screen readers like Jaws do - a well designed website written/coded with the WAI in mind will, by default, be Google friendly. Any modern website should be written in this manner anyway.
Since Google are famously reticent about letting people know exactly how the PageRank algorithm actually works making a site specifically "Google friendly" is something of a nonsense the best you can do is follow best practices and standard SEO techniques and hope for the best - go too far in trying to game Google and they will remove you from their index (ask BMW).
I'm not saying that Google ISN'T becoming the next Microsoft, I'm not saying that they don't abuse their (virtual) monopoly in search and I'm not saying their "do no evil" mantra is complete BS (privacy, what privacy?) - BUT credit where it's due, they do knock out some useful or innovative apps.
Google maps was (IIRC) the first AJaX-ified mapping program - you didn't have to reload the entire page to scroll the map - a winning feature by itself.
Compare Google Analytics to Webalizer which was the bog-standard tool installed before Google Analytics came along - and without Google Analytics we'd not now have Piwik.
Google Earth, Gmail, Translator and so on and so forth - most things Google do are either innovative or better than the competition in some way - that's how they got to be where they are, Google Search was a revelation when it came out; no crappy, slow-loading portal page just a search box and a logo and relevant results.
It might not be healthy for one company to "hold so much power" as you put it but remember, when they started it was just a couple of lads, in a garage, who knocked up something better than all the big boys on the web at that time could manage; there's nothing to say that the same thing can't happen to Google if they rest on their laurels.