The question of whether we should use <STRONG> tags vs <B> tags in one of our larger sites came up recently while we were implementing some changes, based on the recommendations of one of the SEO companies who are consulting with us (at my job).
One company recommended that we use <STRONG>, and not <B>, probably because it is what the WC3 recommends, however, we’ve been using the old bold <B> tag forever.
Being a little bit lazy (I really didn’t feel like making a mass change across a site of over 16,000 pages to change B to STRONG), and also a bit curious, because I could have sworn that I heard Matt Cutts say that it didn’t really matter which you use, I decided to do a little looking around.
It turns out that according to Matt and the actual Google engineers who weight the particular algorithm elements, <STRONG> and <B> are exactly the same when it comes to ranking and optimizing pages.
The exact same goes for EM vs ITALICS tags (<EM> and <I>), no difference at all.
I’d like to personally congratulate Google for “Keeping it Real”.
Also, if you’d like to hear it from the horses mouth, here you go…