Danny Sullivan:

An SEO is someone who understands how people search for information (on the web and in other ways) and ensures that they or their clients are visible in the unpaid listings that are provided. A search marketer, by the way, is someone that ensures listing in both paid and unpaid listings.

SEO is the combination of tactics and strategies, including, but not limited to, optimization of information architecture, usability, content focus, audience targeting, design, development, keyword research, keyword placement, link building, social media marketing and any other online or offline branding/marketing elements that support the goal of receiving more traffic from search engines.

Neil Patel:

Search engine optimization (SEO) is the art of understanding search engines and and using that knowledge to make a website rank high on search engines.

Andy Beal:

Making changes to the on-page and off-page relevance of a web page in an effort to increase the volume of quality traffic from the search engines.

Lee Odden:

Whatever can be searched on can be optimized. Optimization for bots improves content discovery, indexing and trust (algorithmically). Optimization for the user experience improves clickthroughs, conversions and community. People that called themselves SEOs in the past are really just online marketers leveraging a mix of technology, creative and fundamental marketing expertise to make sales online. They’re more marketing consultants then SEOs even though the “SEO” moniker persists.

Definitions of SEO will change as search channels and user behaviors change, so it’s a waste of time to try and create a standing definition - in my opinion anyway.

Michael Gray:

Search Engine Optimization: The process, of building, designing, creating, or updating a website, or it’s contents, with the goals of increasing visibility within search engines, and improved placement on search engine results pages, for a desired set of keywords terms or market segment.

Marcus Tandler:

The practice and methods of improving a website´s ranking in the organic results of searchengines.

Dax Herrera:

Google’s mission is to organize the world’s information and make it universally accessible and useful.

The SEO’s mission is to organize the client’s information and make it robotically accessible and profitable.

Patrick Gavin:

The art and science of raising a web page’s natural search engine rankings. SEO is broken into two distinct buckets: on page factors and off page factors. On page factors including such items as: a website’s crawl-ability, internal linking set up, keyword selection and placement, meta tags, etc. Off page factors being building link popularity (inbound links) into your website. I believe link building to still be the single most important part of the SEO equation.

Aaron Wall:

SEO is the art and science of publishing and marketing content in a way that brings significant profitable and targeted traffic to your website. As the web has grown and Google has become more sophisticated, the field of SEO has been aggressively merging with traditional marketing, with emphasis on branding, framing, story telling, user engagement, viral marketing, and public relations.

Abraham Lincoln once said “With public sentiment, nothing can fail. Without it, nothing can succeed.” That is where profitable sustainable SEO is headed.

Rebecca Kelley:

In my opinion, SEO is simply a facet of traditional marketing that focuses on the Internet medium. It involves implementing strategies and changes that make your website both search engine and user friendly — search engine friendly so that your site ranks well in search engine results for appropriate keyword searches, and user friendly so that you can provide a solid customer experience and yield high conversions.

Darren Rowse:

How do I define SEO? Good question - there are a number of thoughts that come to mind:

1. the right answer - SEO is something that helps a website to increase it’s ranking in a search engine.

2. my ‘historical’ answer (ie what I would have answered a few years ago) - SEO is about manipulating Search Engines in order to get them to send you as much traffic as possible.

3. the ‘in practice’ answer (ie how it impacts me these days) - SEO for me these days is a combination of:

• about knowing some of the general principles that help a site or page to rank well in search engines
• building the best quality site that I can with content that meets the needs of readers (and as a result attracts links from other sites).

I guess I’ve come to learn that when you build a high quality website that SEO tends to largely look after itself.

Ted Murphy

SEO is the art of optimizing an online presence in order to maximize relevant search engine traffic.

Stephan Spencer:

In our view (here at Netconcepts), SEO is the application of techniques that make websites and web content more findable for particular keywords being searched on by search engine users. While SEO is not a hard and exact science (there is definitely an art to it), SEO experts do seek to apply rigorous logic to reverse engineer the “black box” that is the search engines’ algorithms, in order to “deconstruct” (identify, quantify and qualify) the hundreds of factors which play a part in search engine ranking. From those factors, SEO practitioners derive methods to engineer webpages whereby search engines will favor their content in the rankings. Classically, SEO addressed more simplistic factors such as the “spiderability” of sites/pages and the tuning of technical factors found directly on the pages and within the website’s architecture (such as URL structure). However, as the search engines continue to evolve, advanced contemporary SEO practices increasingly need to include attention to off-page factors which address meta-data about the linked content. These include, among other things, more subtle and indirect strategies such as syndication, viral marketing, social media “optimization”, and community-building efforts.

Joost Devalk:

Search Engine Optimization is the practice of improving a sites’ content, code, server settings, internal structure and external linking, with the intent of making the site rank higher in the search engines. If done well, SEO is a part of each (online) marketing act, resulting in the improved visibility of the site.

Note that I do NOT think that a site should rank higher than “it’s meant to be” if there IS such a thing. In the end, SEO should make a site WORTHY of a higher ranking, not push it beyond what it’s worth. In practice, this means that if a site is sh*t, link building for it is neigh to impossible, so it won’t work, and we’ll tell people to improve their site. That means that in the end, an SEO is more off a total online marketer and site consultant than just someone pulling some tricks to quickly make a site rank better.

Quadzilla aka Seo Black Hat:

“ Web spam SEO is when somebody tries to cheat or take shortcuts so that their Web site shows up higher [in search results rankings] than it deserves to show up,” - Matt Cutts QuadsZilla

Todd Malicoat:

SEO is an evolving marketing school of thought born from the desire to rank high in search engines…not a process. It is the art and science of blending user experience, conversion, monetization, and search-ability for optimal web site performance. The irony with SEO is that the acronym is poor marketing created by a new generation of marketers - it should be WSO - Web Site Optimization.

Tamar Weinberg

SEO is a form of internet marketing that entails designing websites for search engine awareness and visibility as well as for user friendliness (especially with regards to relevancy). SEO is on-page optimization that focuses heavily on improving the site’s content with an emphasis on keywords in the site’s architecture, which includes link structure, navigation, title tags, and other on-page elements.
Thanks everyone for participating.

Chris Winfield:

SEO is a component (one of the most important) of Internet marketing. Good SEO entails (a) giving a search engine spider what it wants (b) creating, or optimizing, great content and (c) getting quality websites to link to your website. Good SEO will result in targeted traffic and will drive sales.