The differences between search engines are the algorithms that process the search using various components such as relevance, date issued, location and paid ads also contribute to the search results.
Bing vs. Google:
Bing identifies with pictures, video, audio, flash. Bing is much more capable of understanding flash and images. Bing’s interpretation of images is far greater than Google’s, Bing uses what’s known as “entity understanding”, which allows Bing to determine whether an image is of a person, place or object. Bing favors direct keywords & less backlinks. Bing relies more on ‘direct’ keywords. You should try to keep your web pages specific around a particular keyword, as well as in your backlinks, internal and external. Bing also relies more on internal backlinks with specific keyword anchor text. In terms of external links, Bing tends to favor websites with a smaller numbers of backlinks, but of higher quality sites. The method that Bing uses to rank websites relies much less on backlinks than Google. Instead, as a newer search engine Bing puts more emphasis on social media, and ironically even on Google+ usage.
Google relies more on text based content and descriptions for pictures. Google’s search bot doesnt recognize Flash, so any websites developed in flash will essentially disappear. Flash is becoming something of the past, with many web developers favoring more “search friendly” and more flexible HTMLs. Google is much better at deciphering a page’s purpose within a context.
Bing/Yahoo & Google SEO Differences
Bing/Yahoo and Google have both subtle and notable differences, respectively:
Google: Google’s algorithm recognizes synonyms and context around a keyword. This allows a little freedom and creativity with your content
Bing: Exact keywords are best here
2) Double-Meaning Search Queries
Google: If there is a keyword phrase with two meanings, the most popular website tends to rank first
Bing: A double meaning search in Bing provides local results first
3) Domain Age/Page Authority
Google: Domain age does not factor in as much as the quality of backlinks pointing towards a domain. Also, Google does give favoritism towards .edu and .gov, as they tend to have quality links and good content
Bing: Puts importance on domain age when assigning rank, as well as favors .edu and .gov websites
4) Flash Content
Google: Google cannot crawl and understand Flash websites
Bing: Understands and crawls Flash websites very well and sometimes gives credit to websites that use it
As you can see, Bing, Yahoo and Google all play a very important role in SEO and it is important to optimize for all. Just because you are ranking well in one search engine, does not mean you are ranking well in others.
5) Mobile Optimization
A little over a year ago, in November, Google launched the mobile-friendly label on mobile search results. This label is grey wording that is placed underneath the link that tells the user whether the website is going to work correctly on their mobile device or not. Starting on April 21st, 2015, Google has announced that they will be adding a ranking factor that will help mobile-friendly websites rank better in mobile search, so it is very important that website owners be prepared for this change.