Shoutmix , chatbox and tagboard are totally the same thing. Shoutbox is a place on Internet where you can shout what you want without(or somethimes needed) registration or etc. They are usually public and are like , to send comments for a thing , or for people to comment what you say
smf shoutboxes, vbulletin shoutboxes, wordpress shoutboxes are shoutboxes for a special website. For example , Wordpress is a tool for blogging , and if you need a shoutbox on your blog - you can use that one , vBulletin is a forum script and you can use that vBulletin shoutbox for a forum. Etc. Etc.
There is thing like Flash shoutbox , because Flash can't store a shoutbox. You need a free website which hosts the flash shoutboxes , and you can add the HTML in your page.
You can't create a shoutbox by uploading a flash file , but you can if you insert a code like <embed src="www.someotherwebsite.com/shoutbox.swf?id=34w4w34"> and it should work.
Do you have a website , Facebook fanpage or something? Where are you going to use it

?