In reviewing Matt Cutts Qualities of a good site video, one of the questions that came up was the use of <b> v.s. <strong> and <i> v.s. <em> tags. It’s one of those esoteric details that make up the world of SEO. For those of you who don’t know, my attempt at the technical definition of these tags is as follows:
- <b> – Will present the encapsulated text in bold font, but is not meant to change the semantic meaning of such text. For example, if you read the sentence that contains text inside <b> tags you should read such encapsulated text with no special emphasis at all.
- <strong> – Will present the encapsulated text in bold font, and is also meant to change the semantic meaning of such text. For example, if you read the sentence that contains text inside <strong> tags you should read such encapsulated text louder and more “boldly”.
- <i> – Will present the encapsulated text in italics, but is not meant to change the semantic meaning of such text. For example, if you read the sentence that contains text inside <i> tags you should read such encapsulated text with no special emphasis at all.
- <em> – Will present the encapsulated text in italics, and is also meant to change the semantic meaning of such text. For example, if you read the sentence that contains text inside <em> tags you should read such encapsulated text with additional emphasis.
There is a pretty good forum posting about bold vs strong and italic vs emphasis tags here. Note that the W3C recommends that we all use <strong> and <em>.
So now, onto SEO. In one of Matt’s Qualities of a good site video, he reported that Google had a slight preference for bold <b> tags over <strong> tags. I imagine that this caused a grand rush for thousands of website owners to tweak their sites.
But you can stop the presses! Matt later recanted on this comment in his Lightning Round. One of Google’s engineers evidently showed Matt the specific code that addresses this issue. Google treats the <b> v.s. <strong> exactly the same, Google treats the <i> v.s. <em> tags exactly the same.
So what does this mean? If you are into the finer details of the semantics of markup, use <strong> and <em> tags. If you are into minimizing typing time, use <b> and <i>. We personally prefer to use <strong> and <em>, as we are simply in the habit of maximizing compliance with standards and recommendations, whenever it does not interfere with business results (which is most, but not all of the time).
