@victor Yes and No… I mean… Google is almost the only search Engine I take seriously but this doesn’t mean I simply do not optimize for other search engines or I completely ignore their rules.
Here are some facts for you:
1. Most other search engines populate their results with Google search results.
2. If you rank very highly in Google their is a better chance of you ranking even better in Bing or Yandex or Yahoo or whatever else you like.
3. The requirements are really not all that diifferent.
4. (This one might surprise you). If you suffer a Google penalty there is a 99.9% chance you will have suffered a ban from Bing and Yahoo as well…
So why not just focus on making your website Google worthy? I have hardly had a website doing more than a couple hundred hits from The likes of Bing and Yandex et Yahoo combined. They just don’t drive as much traffic as Google would… But guess what? I am still the first guy who would Open up a Bing webmasters account for a new website. Still the same guy that will go back every month to find errors on my site and fix. I don’t really know why I do that… But maybe I am hoping someday down the line I would be terribly wrong and i would start getting hundreds of thousand of hits from Bing.