Should I be aiming to rank highly in all search engines, or just focus on Google?

This question is unfortunately very short and sharp.

Fundamentally, Google is the only search engine that actually would give you a ROI on your SEO.

End of story.

The same market shares apply with paid search. Focus on Google.

If you were marketing outside Australia, it’s a different story, but, for now, Google needs to be top of mind for any start-up.