In brief
- SEO splits into three foundations (technical, on-page content, off-page authority) and a set of specialisations defined by business model or device: local, mobile, e-commerce, B2B, enterprise and others.
- Search engines work in stages: crawl, index, serve. Most SEO problems can be traced to one of those stages, which tells you which discipline fixes them.
- No type of SEO can guarantee a ranking. Google’s own documentation says no one can, and warns against agencies that promise it.
- Choose disciplines by how your customers search and buy, not by what a vendor happens to sell.
- Each specialist guide goes deeper on one discipline. This page is the map.
Part 01
Why SEO still matters
Search is the moment where intent is explicit. Someone typing “mobile SEO agency Austin” has told you what they want, where, and roughly how ready they are. Paid ads can rent that moment. Organic visibility earns it repeatedly without a per-click bill, which is why its value compounds over years rather than campaigns.
The surface is changing. AI-generated overviews, map packs, video carousels and shopping results now share the page with the classic list of links. The work underneath has changed less than the headlines suggest: pages still have to be crawlable, understandable, fast, and worth citing. The disciplines below are how that work gets divided.
What SEO cannot do
Google’s guidance for businesses hiring an SEO states plainly that no one can guarantee a number-one ranking. Treat any guarantee of position, timeline or traffic as a reason to ask harder questions, not a reason to sign.
Part 02
How search works
Every search engine does three things in sequence. Knowing where a problem lives tells you which kind of SEO fixes it, and which kind is being sold to you when it should not be.
Crawl
Automated fetchers such as Googlebot discover pages by following links and reading sitemaps. A page that is blocked, orphaned or too slow to fetch never reaches the next stage.
Index
The engine renders the page, works out what it is about and decides whether to store it. Duplicate, thin or noindexed pages are dropped here, quietly.
Serve and rank
For each query, ranking systems choose the most relevant, helpful results from the index, taking the searcher’s location, language and device into account.
Part 03
The three foundations
It helps to separate the foundations every site needs from the specialisations that depend on your business. The foundations are not optional, and no specialisation makes up for a missing one.
- Inner ring: foundations
- 01TechnicalLive
- 02Content
- 03Authority
- Outer ring: specialisations
- 04AI-powered SEOLive
- 05B2B SEOLive
- 06E-commerce SEOLive
- 07Enterprise SEOLive
- 08Local SEOLive
- 09Mobile SEO
- 10WordPress SEOLive
Technical SEO
Crawlability, indexing, rendering, speed, structured data and the health of the server. The plumbing. When it fails, nothing downstream matters.
On-page content
Pages that answer the query completely, are organised so engines can understand them, and are written by someone who demonstrably knows the subject.
Off-page authority
Links, mentions and citations from sites that already carry trust. Earned by being worth referencing, not by buying placement.
Part 04
Specialisations, and which one fits
Specialisations apply the foundations to a specific business shape. Most companies need the three foundations plus one or two of these. A regional law firm is local plus technical. A direct-to-consumer brand is e-commerce plus mobile.
Specialisations by what defines them
| Specialisation | Defined by | Typical first job | Guide |
|---|---|---|---|
| Local | Searches with a place in them, or near-me intent | Business Profile accuracy, location pages, review handling | Local SEO |
| Mobile | The device most of your visitors are holding | Responsive layout, speed, content parity with desktop | Mobile SEO agency |
| E-commerce | Catalogue size and product pages | Faceted navigation, product structured data, duplicate handling | E-commerce SEO |
| B2B | Long cycles, small audiences, many stakeholders | Problem-aware content, comparison and evaluation pages | B2B SEO |
| Enterprise | Thousands of pages and many owners | Governance, templates, crawl budget | Enterprise SEO |
| WordPress | The CMS, its theme and its plugins | Theme performance, plugin hygiene, clean URL structure | WordPress SEO |
| AI-powered | Tooling that accelerates research and QA | Entity coverage, structured data, content audits at scale | AI-powered SEO |
The common mistake is buying all of them as a bundle before knowing which stage of search is actually failing. An audit that names the failing stage, with URLs, is worth more than a proposal that lists every service.
Part 05
What an SEO engagement should include
Whatever the specialisation, the shape of serious work is recognisable. Use this as a checklist when reading proposals.
Reasonable to expect from any proposal
0 of 5 tickedReason to pause
- Guaranteed rankings, traffic or timelines
- Methods that cannot be explained, or link sources that are not disclosed
- Reports that only show keyword positions
- A bundle of every service before an audit
Reasonable to expect
- Specific findings tied to URLs and templates
- Timelines with their assumptions stated
- Plain-language explanations of each change
- A scope that matches the failing stage of search
Part 06
How to use these guides
This page is the overview. Each specialisation has its own guide that goes one level deeper on the questions to ask, the work involved and how to measure it. Start with the guide that matches the way your customers search, and return here when you need the wider map.
The newest guide is What to Know When Looking for a Mobile SEO Agency. The others open on the current site in a new tab.
Questions readers ask
Is technical SEO the same as web development?
They overlap but are not the same. Technical SEO identifies what prevents pages from being crawled, indexed, rendered or loaded quickly. Developers implement the fixes. A good engagement defines who does which part before the work starts.
How long does SEO take to show results?
It depends on the site's starting condition, how competitive the market is, and how quickly changes are published. Google's starter guide notes that changes can take anywhere from hours to several months to be reflected in results. Be cautious of any specific promise.
Does local SEO replace the rest?
No. Local SEO adds Business Profile, location and review work on top of the foundations. A slow or un-indexable site still underperforms in local results.
Do we need a separate agency for each type?
Usually not. Most agencies cover the foundations and one or more specialisations. What matters is whether they can show work in your category and explain their plan in plain language.
Do FAQ sections like this one get special treatment in search?
Not as a rule. In 2023 Google limited FAQ rich results to a small set of authoritative government and health sites, so FAQ markup is not a route to extra visibility. We include questions because readers ask them, not for the markup.
Sources
- In-depth guide to how Google Search works — Google Search Central
- Search Engine Optimization (SEO) Starter Guide — Google Search Central
- Do you need an SEO? — Google Search Central
- Creating helpful, reliable, people-first content — Google Search Central
- A guide to Google Search ranking systems — Google Search Central
- FAQ (FAQPage) structured data — Google Search Central
- What to Know When Looking for a Mobile SEO Agency — DIGITECH, this guide family
- Technical SEO Agency — DIGITECH, published site
About this guide
Written by
Maya ChenDirector of Search Strategy
14 years in search · Leads SEO and AI search programs for behavioral health and specialty care
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Maya leads the search practice at DIGITECH. She plans the SEO and AI search programs behind the agency’s behavioral health and specialty healthcare accounts, and writes about how families and patients actually research care. Her work starts with the question a person types, not the keyword a tool suggests.
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Elias MorganEditorial Director
Former healthcare trade editor · Checks every guide against its cited sources before publication
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Elias runs editorial review for everything DIGITECH publishes. He reads each draft against the sources it cites, checks the claims a client could be held to, and signs off on the review date that appears on the page. Before DIGITECH he edited a healthcare trade publication for eight years.
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