Official answer: <strong> is semantic-- well, sort of-- while <b> is unequivocally presentational. You can define either one in your CSS to look like whatever you want it to look like.

<b> is bold. <strong> is what the browser decides it should be. Right now it happens to be bold, as <em> happens to be italic. At least in English.

<groan> :-)

I agree and use strong . . . . but many use b (and i, as opposed to em) because devices still know what the heck it is. Whether you're strong or bold, you're still "macho." :-) The one (sorta) good argument for b is that it requires less bytes than strong (and less to type).

foray over strong and bold [webmasterworld.com] <- There are about 2,000 or so of these. Google strong b site:webmasterworld.com

It's almost as highly argued as tables for layout . . . but you learn a lot about things reading through those posts, and many of them make good cases (in spite of the spec)

Does it matter, for SEO, screen readers, accessibility, price of tea in Marphoackdupenot? No. :-)

<b></b> tags are used to create boldface text on the page. While visually browsers typically render <strong></strong> tags as boldface text as well.

In HTML5 <b> and <i> have specific meaning as do <strong> and <em>. Use them all as specified.

4.6.2 The em element
[WHATWG.org...]
www.WHATWG.org/specs/web-apps/current-work/multipage/text-level-semantics.html#the-em-element

4.6.3 The strong element
[WHATWG.org...]
www.WHATWG.org/specs/web-apps/current-work/multipage/text-level-semantics.html#the-strong-element

4.6.16 The i element
[WHATWG.org...]
www.WHATWG.org/specs/web-apps/current-work/multipage/text-level-semantics.html#the-i-element

4.6.17 The b element
[WHATWG.org...]
www.WHATWG.org/specs/web-apps/current-work/multipage/text-level-semantics.html#the-b-element

While you're at the above links, you might want to review other changes that have taken place with some of your favorite HTML Elements. For example, check out <s> and <u> Elements which have been deprecated in HTML4 but are alive and well in HTML5 and have specific meaning. Wait until you see what the <u> is used for. ;)

Note: You may have to cut and paste the URIs, the Fragment IDs are not working from here, they are getting stripped in the redirect. :(

Thank you all for your response.

Wait until you see what the <u> is used for.

Oh my gosh. Right now as we speak there's a heated discussion on my e-books forum about this very function. That's function, not presentation. (In our case, flagging typos in the original.) Now if only they could drop their morbid fixation on XHTML and adopt HTML 5...

I use <em> in forms like
p.ital em {font-style: normal}
Meaning that if the body text is italic (very common in 18th-century material, but also useful in modern contexts) it toggles to roman for emphasis. In a non-CSS UA, the whole package flipflops so you retain the emphasis.

Wait until you see what the <u> is used for. ;)

Some of the current arguments about redefining old html elements reminds me of arguments made regarding how society ought to treat criminals. Some people want to reform these non-conforming elements, others just want to kill the f-ers.

Does it matter, for SEO, screen readers, accessibility, price of tea in Marphoackdupenot? No. :-)

I just performed a quick search for tea prices in Marphoackdupenot and was delighted that I wasn't "forced" to leave either Bing or Google to find the answer! ;-)

While <strong> is of course more semantically correct, there seem definite legitimate reasons to use the <b> for customer-written content.
Search Engines refer <strong>

I see it differently, James. <b> is for visual presentation only - no change in meaning is intended. <strong> imparts semantic strength to the content (a louder voice, if you will.)

Search engines are doing all kinds of things today, and mark-up like this has a lot less power than it use to. Any time the average website is inconsistent in the technical use of some tag or other, the search engines need to compensate - just as they have for <h1>, for example.

<b> is less memory used over <strong>.

IIRC <strong> and <em> were intended to coach voice readers... but somewhere along the way that all fell to doodly squat, so I'm not sure where everything is these days. Thus, <b> and <i> work for me and I see no reason to change... yet (and a simple sitewide search and replace can fix these if it ever needs to be fixed).

So I'm not sure where everything is these days.

I am. Links posted above. In HTML5 all 4 elements have specific meaning.

<b> is less memory used over <strong>

I'm going to refrain from making a diplomatic comment on that one. ;)

I don't know of a WYSIWYG Editor that allows you to use all 4. It's either <b> and <i> or <strong> and <em>. With WordPress, it's <strong> and <em>. A true browsing nightmare for anyone using screen reader/speech browser software. Ya, I know, who uses that stuff?

The links provided above seem to be broken one's now... But, thanks for peaking my interest. I am wondering, though, if a site is using a tag in the wrong way, could this work against a page/site and affect rankings?

How many are coding HTML 5 right now? Or updated their x-years old sites to that? How many browsers are fully HTML 5 compliant? Has HTML 5 actually been finalized and rolled out? Serious questions. Which is a prediction why it might take another 15 years for the web to really "change".

How many are coding HTML 5 right now?

Everyone in my circles are using HTML5. Google is using HTML5 and has been since 2008.

How many browsers are fully HTML 5 compliant?

As far as I know, most of the later browser are HTML5 compliant. They may not be "fully" compliant but we're that far along where using an HTML5 DOCTYPE is now the norm. For some of us. ;)

Has HTML 5 actually been finalized and rolled out?

Latest published version is a Working Draft from May 25, 2011. And no, it is not officially rolled out. But, it has been in the works for 3+ years and most of the spec is complete. There are some remaining issues that are being addressed and I would expect to see official rollout this year or next.

You can safely use the HTML5 DOCTYPE from my perspective. I've been using it for 2+ years now.

I am wondering, though, if a site is using a tag in the wrong way, could this work against a page/site and affect rankings?

I doubt that element misuse would mess with rankings too much. I've noticed little difference, if any, between <b> and <strong> from an SEO perspective. The correct use of semantic elements should be taken seriously if you take pride in your work and want to provide the best user experience to everyone, but for SEO it doesn't matter much.

While much HTML misuse doesn't seem to matter, it's probably still a good idea to avoid outright spammy-looking things. Wrapping all of your paragraphs in something like <strong style="font-weight:normal">... </strong>, in addition to being ineffective for SEO, might be tempting fate a little too much.