<strong> HTML elements have default black and bold CSS styling.

I want my strong elements to have light blue background, have blue as font color and underline strokes.

But does changing the default <strong> element have affect on SEO? I remember Google penalized such kind of changes a while ago. Is it still so?

Also should I override the <strong>element by a strong rule or should I create a class rule and add the class to all strong elements?

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    None of this affects SEO. Even the effect the <strong> tag has on SEO is so small that it isn't worth consideration. Just style it however works best for you and move on.
    – John Conde
    Commented Dec 25, 2015 at 16:31
  • Thanks. Actually, I just want to achieve this right way. I thought it might also affect screen readers for visually impaired people or maybe other things. I should have my styling but without breaking the standards.
    – Jessia
    Commented Dec 25, 2015 at 16:40
  • Style how you want - just do not get carried away.
    – closetnoc
    Commented Dec 25, 2015 at 16:59

1 Answer 1


Does changing Strong element CSS styling affect SEO??

Absolutely not.

Two conflicting versions of the original research paper by Brin and Page at Stanford University, describes Google before it even began. The experimental/research version of Google (still exists by the way - the last time I looked anyway) laid the foundation for the commercial product.

In these documents, one describes various styling as being fancy to be indicated within the index. These include mark-up such as bold, italics, capitalization, etc. This is before CSS (cascading style sheets) when HTML coding was still fairly basic. These indications were for single terms within the index and stored in a binary format to indicate what kind of fancy was found for the term.

One thing that Brin and Page emphasized constantly over the years, is that any stored data must have significance. The reason for this is simple. Hard drives were and remain expensive and relatively small and therefore indexing capacity was limited though much storage potential has raised significantly over they years. It remains true that storage is a premium. While it was not made clear that I can see, indications that I can find seems to elude that some of these fancy indications were found to be statistically insignificant and may have been dropped as this binary storage technique has changed and been expanded over the years.

Keep in mind that from the very beginning, Google was intended to be a semantics search engine and does not make direct term matches but rather attempts to match search intent using semantic analysis. This has been significantly expanded to near full capacity with major leaps in semantic capability beginning in 2002, 2003, 2005, and 2008, and continuing. As part of semantic analysis, fancy does not apply though it can still be used. However, semantic analysis of HTML uses the DOM model and fancy does not fit this model.

Was/Is there a penalty for style HTML mark-up??

No. Or at least only temporarily in limited forms.

Keep in mind, most SEOs are not technical people and glom onto anything they think may be significant or an advantage.

At some point, it was decided that bold and italics amongst other forms of fancy contained an advantage, however, this was not true at the time. As a result, many sites began to try and take advantage of this. I do not believe that there ever was a specific penalty for this behavior, however, fancy was at least ignored and sites that attempted to abuse this ideology, may have been singled out as spam through manual means or other forms of analysis.

Now that CSS exists and little HTML mark-up contains fancy, the complexity has been greatly expanded. I do not believe, in light of the emphasis upon semantic analysis, that fancy was ever expanded or emphasized to include styling mark-up. Semantics is about content analysis and not style.

So does style matter for matching search intent to content??

No. At least not for semantic analysis.

While style does matter for user experience, fancy remains completely ignored for matching search intent to content. This is evidenced in how SERP snippets that are not taken from the description meta-tag are taken and presented. You will not find matches for content marked with style as an indication nor will you find header tags and other similar mark-up. You will find that straight content often found in paragraphs, blockquotes, tables, etc., are used.

  • Link to the experimental Google please... :D is it research.google.com
    – undo
    Commented Jan 2, 2016 at 12:36
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    @RahulBasu It used to be at google.stanford.edu but I do not exactly see it any more. It was available not too long ago. Not sure if it was moved or taken down.
    – closetnoc
    Commented Jan 2, 2016 at 16:40
  • No problem... web.archive.org/web/19981111183552/http://google.stanford.edu
    – undo
    Commented Jan 2, 2016 at 17:06
  • @RahulBasu Nicely done!! I updated my answer to clarify that statement. It was there almost 20 years... funny they should decide to take it down now. I would have kept it up for historical reasons even if I needed new hardware. Maybe they will bring it back.
    – closetnoc
    Commented Jan 2, 2016 at 17:13
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    @Yako Sorry! ;-) Fancy is bold, italics, font sizing larger or smaller than the rest of the text, superscript, subscript, underline, capitalization etc. Basically styling. As for capitalization, there is are several forms, sentence case, all upper case, title case, etc. Capitalization is the only fancy that we know exists today. Even as far as the research paper goes, there are two versions that appear exactly the same with the exception of (at least) the mention of whether fancy is indexed in the proof of concept search engine.
    – closetnoc
    Commented Apr 23, 2016 at 22:57

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