martinibuster - 5:14 am on Sep 18, 2012 (gmt 0) [edited by: martinibuster at 6:14 am (utc) on Sep 18, 2012]
That paper was from a long time ago, when Brin and Page were still in school. While it describes the foundation of PageRank and reading that document is essential to beginning to understand SEO, Google has also come a long way since then. Bill Slawski's blog [seobythesea.com] is the best source of Google patent information that details just how far Google has come.
As far as the part you quoted, that's a reference to font size, not specifically heading tags. I am quite familiar with that passage. Back in 2003 I wrote about that specific passage you quoted in a post on WebmasterWorld about Big Font SEO [webmasterworld.com].
That passage does not specifically address heading tags and much less it does not specifically address the current state of how H1's are handled. How could it?
Here is some reading on Bill Slawski's SEOBYTHESEA blog that begins to touch on the complexity of heading tags, how they're not just a ranking signal on a list of signals that has to be ticked off to rank well (title tag, h1, bold, italics, etc.). This article is a good one to start with: [seobythesea.com]
When you use a heading element, whether <h1>, or <h2>, or so on down the line, you aren’t just impacting the look and feel of the text within that element, but you are also defining a semantic relationship between those words and the words that follow them.
...When you use a top level heading, or an <h1>, you’re setting up a semantic relationship between that heading and the remainder of the content on a page, describing what it is about.
Weight of Headings Defined by How Well They Describe a Semantic Relationship?
Heading elements can help a search engine understand the semantics of words on a page a little better. Search engines can go out on the Web and index pages and explore the relationships between terms within headings, and the content they describe within that index. They can look for similar relationships on all the documents within their body of web pages that use the same terms within headings, and see if there might tend to be some kind of co-occurrence of words and phrases and concepts within those matches of headings and content using those headings.
Bill Slawski also describes a patent issued to Microsoft [seobythesea.com] that mentions the use of heading tags as a way of identifying blocks of content for the purpose of:
•Clustering the pages with other similar pages
•Extracting Topics from those pages
•Breaking Pages apart for display on handheld devices
•Highlighting Blocks that might be of interest to searchers
•Summarizing content, and
So you see, the put the main keyword phrase in the H1 element isn't the only way to look at it. The way search engines are looking at the web page, particularly in terms of concepts, has evolved.
[edited by: martinibuster at 6:14 am (utc) on Sep 18, 2012]