Some of you may know that text that has been marked as bold or italics registers as more important than plain text on websites, according to search engines.
Matt Cutts, who heads Google's Webspam team, had released a video a couple of years ago that clears up a few questions regarding these SEO tips and techniques.
First, while you want to keep SEO in mind, you want to primarily design your site for your users. If you think it will enhance readability, then use bold or italics. Just don't over do it, it can hurt your user's experience and make crawlers think you're spamming. (You can find some more tips to help improve SEO and user's experience.)
I ran across some wrong information relating to bold and italics and wanted to clear some of that up here.
Do Bold or Italic tags increase SEO?
They both do in most cases. Search engines see that you're highlighting these terms and will put greater emphasis on them when indexing the site. How much weight they apply varies and Matt Cutts explained that Google does take this into consideration but it is very minimal overall. Like many other things, as people abuse it, it gets less weight. So use it sparingly and primarily for your users.
You have to use the actual tags in the HTML though and not just in the stylesheet (.css) file. Crawlers don't really care about formatting and I've never noticed a legitimate spider access any .css files on my sites.
Is <strong> or <b> better for SEO?
This is something I had a question about not too long ago. I never really gave it much thought and always used
<b>because that's what I was accustomed to from early on. Back when I started playing around with HTML I don't even remember there being a
Bottom line according to Matt Cutts, Google treats both tags the exactly the same. At least they did back in 2006 when he made the video.
The W3C recommends the use of
<strong>because it conveys importance and not just formatting. Some screen readers also prefer strong over bold.
Is <em> or <i> better for SEO?
The answer to this question is the same as for bold vs strong. Google treats both the same but it is recommended to use
<em>to convey emphasis and not just that you want to have the text displayed in italics. Both will give you the same visual results.
To have an accessible website stick with
<em>but don't start pulling your hair out making changes throughout your site in the hopes of increasing your search engine rankings.