None of these are SEO. SEO means search engine optimized - something you do to make a website come up on search engines. If you're asking which search engine is best, that should be a no-brainer
Seo means optimizing your website so that it may come up in first page for certain keywords .I think you are asking for : on which search engine you should target seo ? .That will be google as still majority of surfers comes from google.
Search engines yahoo and MSN do not care so much about the quality of links over the quantity, google looks for better quality links So you can dump loads of links to a site and get ranked in yahoo and MSN easily, but it wont bring in that much traffic as opposed to being ranked for the same keywords in google, also those loads of low quality links will affect your google ranking. The way to get ranked in all three is to build loads of quality links A quality link does not necessarily mean on a high ranking page, although that is good in itself, what they look for is links that are genuine votes for a website not repeat content mass submitted links using the same description each time, as its obvious these kind of links are not genuine votes and not natural
For me, Google is more reliable because as what i have experienced, Google's PR rating is one of the distinguishing factors in having a quality and popular website wherein most of us rely and consider on.
Google delivers more traffic, but is harder to SEO, Yahoo is a bit easier, especially for on-page SEO, MSN is crap - very easy and no traffic.
maybe you wanted to know which search engine to focus on. It is probably best to focus your SEO efforts on google and the rest will most likely fall into place.
the best search engine for you which bring you more visitors , BTW SEO means optimizing site for all search engines not a specific one
Which SE giving more traffic to your website don't worry about that Which one giving less traffic to your website try to Optimize for it.
what would deliver more traffic ? Google, Yahoo or MSN ? so depending on that you optimize for a particular search engine.