To post an image, just enclose the address to your picture inside of the [img] tag:

[img]http://www.site.com/picture.jpg[/img]

The above tag would post the image located at the address shown.

Any address you post that begins with "http" will be formatted into a clickable link:

http://www.google.com

An address like the one above will automatically be formatted as: http://www.google.com

If you want to add a description to your address, you can use the [url] tag:

[url=http://www.google.com/imghp]Google Images[/url]

The above tag would make a link like this: Google Images

To make bold text, use the [b] tag:

I want to make [b]this[/b] text bold.

Would look like: I want to make this text bold.

To make underlined text, use the [u] tag:

I want to make [u]this[/u] text underlined.

Would look like: I want to make this text underlined.

To make italics text, use the [i] tag:

I want to make [i]this[/i] text italics.

Would look like: I want to make this text italics.

If you want to hide part of your post so that the reader must click a 'Show Spoiler' button in order to view it, simply enclose the part of your post that you wish to hide using the [spoiler] tag:

The movie was great.

[spoiler]I especially liked the part where Dr. Evil finally kills Austin Powers.[/spoiler]

One common use for this would be to talk about something like a movie, while hiding parts of your post that would "spoil" the experience for someone who hasn't seen it yet. However, use your imagination here...

To post a YouTube video, use the [tube] tag. Just copy the address of the page where the video appears and then put it inside of the tag. For example:

[tube]http://www.youtube.com/watch?v=LC-jtF3JQ68[/tube]

The above tag would show the video which is found at that address. Optionally, you can also use the video ID by itself, like this:

[tube]LC-jtF3JQ68[/tube]

The tag above would show the same video.

To post a MySpace video, use the [myspace] tag. Just copy the address of the page where the video appears and then put it inside of the tag. For example:

[myspace]http://vids.myspace.com/index.cfm?fuseaction=vids.individual&videoid=25992858[/myspace]

The above tag would show the video which is found at that address. Optionally, you can also use the video ID by itself, like this:

[myspace]25992858[/myspace]

The tag above would show the same video.

To post a Google video, use the [gvid] tag. Just copy the address of the page where the video appears and then put it inside of the tag. For example:

[gvid]http://video.google.com/videoplay?docid=7378275554029349559[/gvid]

The above tag would show the video which is found at that address. Optionally, you can also use the video ID by itself, like this:

[gvid]7378275554029349559[/gvid]

The tag above would show the same video.

If you want to show HTML code in a post (for example, to help someone out with using HTML) you will need to place it inside of a [code] tag so that the HTML code is displayed literally instead of being processed. For example:

[code]<a href="http://www.google.com">Google</a>[/code]

Would look like:

This way, the actual HTML code is shown. If the [code] tag were not used, the HTML would be interpreted and instead of seeing the code shown above, you would only see a link to Google.