I haven't seen many weblogs that require BBCode, I have to say, but there are lots of discussion boards that require postings be written in BBCode rather than HTML. The main reason, as far as I can tell, is so there's some control over people not adding unauthorized HTML sequences (like including pictures from unaffiliated Web sites) because it doesn't seem that much easier than HTML when you look at the two.

Be that as it may, there are now a lot of different sites that are BBCode enabled, so let's have a look at how it works...

The basic difference between BBCode and HTML is that while HTML uses < and > to surround tags, BBCode requires that you use [ and ]. Once you realize that, it's pretty smooth sailing.

For example, bold text is produced with [b]text to have in bold[/b], while italics is generated with [i] and [/i] and underlining (which is still a bad idea on a Web page, even in BBCode) is done with [u] and [/u].

Font color and size changes are accomplished with deprecated HTML "font" tag attributes: [color=red]text in red[/color] turns some text red, for example. You can also specify the hexidecimal color equivalent if you're a purist (that is, use [color=#ccff00]), and text size can be specified as a value of 1..29, where [size=1]1=very small text[/size] and [size=29]29=really big text[/size]. The more modern way to specify these type attributes in the HTML world is to use CSS styles, but that's another story. :-)

A surprising number of boards that use BBCode also support special code listing blocks denoted with [code] and [/code]. Within these two tags, all < and > symbols are translated into their displayable equivalent (the HTML character entities &lt; and &gt;) so that you can share HTML code with other board members.

On sites that allow links to be created, there are two ways you can produce a hypertext reference in BBCode. The easiest is to tell the system that you're entering a Web site address -- a URL -- and that you want it clickable. To point to this Web site, for example, you'd use this: [url]http://www.askdavetaylor.com/[/url]. If you want to get a bit more fancy and have a few words that are clickable, then you need to separate the clickable words from the URL of the target site, as with regular HTML. To have the words "Dave Knows" link to this site, use this: [url=http://www.askdavetaylor.com/]Dave Knows[/url].

Finally, a small number of sites will let you include images using the [img] tag. It's completely analogous to the simpler of the URL forms shown earlier, and linking to, say, the cheery Yahoo Instant Messenger graphic on their home page can be accomplished with: [img]http://us.i1.yimg.com/us.yimg.com/i/ww/bt1/msg.gif[/img]. By the way, just because you can include a graphic doesn't mean you should or are allowed to...

That's about it for the BBCode language. You can combine multiple tags in a sequence if you want blue, bold, URLs, for example (you'd use [color=blue][b][url]the URL[/url][/b][/color]). Just make sure that you always close links from innermost to outermost, just like parentheses in your writing!

Hope that helps you figure out how to use BBCode to its fullest!