Below, some ideas on how to optimize hn (<h1>, <h2>, <h3>, <h4>, <h5>, <h6>) tags.
What are the hn tags for?
- They are useful for the user, to better understand the structure in a document. It also matters for design.
- They are useful for the search engines, to understand how the document is structured.
From the article The Biggest SEO Mistakes SEOmoz Has Ever Made – Whiteboard Friday – Moz:
Recommending People Use H1 Tags with Keywords
This mistake is a little bit more subtle. For years, SEOmoz recommended including keywords in the H1 of pages. After we started doing formal machine learning correlation tests we found out that this tactic didn’t actually help very much at all (including the keywords in normal text in bigger fonts worked essentially the same). This was a shame because it meant we wasted time and energy convincing our clients to update their H1s.
Also see Rand Fishkin’s response here.
- There is a lot of theory on SEO which puts less-to-more emphasis on Hn tags. Some put little emphasis, some put more emphasis.
- In my personal opinion, you should first think about having fonts with big size (for titles) and smaller size (for text).
- I would first focus that hn tags are useful to people. To have an article title, and, if necessary, sub-sections. For a category page from an online store, I should have a big title for the title of the page, and smaller titles for products (or sub-categories). For a long article, having h1 tag for the title, h2 tags for sub-headings and h3 tags for sub-sub-headings should do a nice thing.
- Rather than trying hard to meet the on-page criteria, you should focus on getting visitor interactions. The net advantage is greater than meeting 100% a criteria which, anyhow, is lots of time flexible (there are general principles, not necessarily strict & specific rules).
- Should the h1 be different than the title tags? Some thoughts:
- The title tags (<title>Title which appears in Google</title>) have a very big importance for search engines. I would put lots of emphasis on making them relevant to both the search engine (for ranking; example for this would be having the title start with the suggested keywords – more on this) and the user (for click through rate). So, yes, lots of optimization on this.
- The hn tags tend not to matter as much for Google, but do matter for the users, so I would make them more user-friendly than Google-friendly. My personal opinion is to go over the board and actually make them 100% user friendly (it helps with engagement, and this should provide much better results than the on-page factor does) – please note, this is my personal opinion.
- Should you make them different? Only if you need to tell things in hn tags which, for some particular reasons, can’t be said in the <title> tags. For example, a very long title. Another example – focusing more on Google than on the user. My personal take on this is to make the <title> tag and the hn tag the same, most of the times. The better solution would be A/B split testing.
- You should avoid keyword stuffing (putting lots of keywords, one after the other) in pretty much every place on a web site, and also on hn tags.
- It makes lots of sense to use h1-h2-h3-… tags for a long document, which needs to be separated into sections.
- Is it considered by Google to be one of the most important phrase in the large font text, at the beginning of the document? That’s a (probably) yes (the large font text at the beginning of a document is considered to be important). Is it, though, important to have that text in <h1> tag, or can you just have it with a bigger font? Right now, this is not clear, you can just put <h1> if it’s easy to implement.
- Avoid having <h1> tags for other than titles. Don’t put logos, buttons, other images in it.
- Avoid having identical <h1> tags (or <title> tags, or content) on multiple pages of the same web site (it doesn’t matter for rare exceptions in a web site, it can be a problem if a significant percentage of the pages in a web site have duplicate content, be it <h1>, or meta descriptions, or titles, or content, or images, or other things).
- H1 is the most important tag, then comes h2, then h3, and so on until h6. Put in h1 the title of the document, in h2 other sections, less important, in h3 things with even lesser importance and so on.
- If it is difficult (effort / time / money) implementing h1-h3 tags in a web site, you may take into account ignoring the change (so, if you already have titles with big fonts, and it’s difficult to switch to hn tags, you may skip this).
Matt Cutts’ take on these:
Later edit: don’t ignore the tags completely, they are not irrelevant.