I’m really pleased that Michael Martinez of SEO-Theory dropped by to check out my fledging experiments in boldface and SEO, although his shrewd comments remind me yet again why it is so much easier to parrot “common SEO wisdom” than test it.
Anyway, in my test pages, I’ve been flop-flopping which page of each pair has the boldface. At first, it took one to two weeks to see any shift in SERPs, but now Google has decided they are regularly-updated pages, and it’s picking up the changes within a few days now.
I’ve done 4 flip-flops where the only changes were switching which page of the pair was bold, and sure enough, each time I’ve done it, Google soon changes which one of them is listed first, which listed behind a “Similar results” link. I cannot be absolutely sure I’ve isolated all factors, but I think that’s enough for me, Jane Q. Blogger and Squidoo author, to be fairly confident that Google gives a little extra weight to text in boldface.
Of course, in this case, the biggest confirmation is that Matt Cutts of Google said that Google treats <b> and <strong>, <i> and <em> “with exactly the same weight.” Taken literally, “the same weight” could be zilch, but he wouldn’t have mentioned them unless Google gave them some significant weight. The only question is how significant. I’m guessing not much, but — here we go again — I haven’t tested enough to tell.
Note that <b> is actually a bad habit. I should have been testing <strong>. Back in the day, HTML mixed up two fundamentally different things: how to display something (bold, italic) versus what it is (a paragraph, a title, a header, a key word or important point). <b> and <i> are like specifying that you want medium rare without specifying that you’re talking about hamburger. It’s better to use tags to specify THINGS, and CSS to specify (if you must) how they look.