Hi Liz,
Depending on the module you use, there may or may not be support for tags to be associated with your post. The blog module, for example, does not currently allow you to assign official tags to your post. However, this doesn't mean you can't add tags into the content of your post. In fact, that's what many people do. They will add either Technorati tags or del.icio.us tags to make it easier for their content to be crawled by the Technorati bots or to make it easier for people to add your content in del.icio.us. Windows Live Writer has a nice feature built in which allows you to easily add tags for some of the common services, like Technorati and del.icio.us.
Real quick. Technorati is a search engine for blogs as well as a community where other Technorati members can add you as contacts saying basically that they read your blog. I highly recommend involvement in this community if you are going to use your blog as a platform for discussing ideas with colleagues in your industry. There's a process you have to go through to claim your blog, but after you're done with this, you can add Technorati tags to your posts from within Live Writer to say to the Technoratic crowd that you're blogging about these particular issues. You can also configure WLW to automatically ping Technorati every time you enter a post. This is configured in Tools | Options | Ping Servers. For Technorati, just enter the following in the list of ping URLs:
http://rpc.technorati.com/rpc/ping
Of course, I imagine you're already using del.icio.us and are aware that adding tags to your post just makes it easier for others to quickly add a bookmark to your post along with keywords that you recommend.
So, in summary, some modules support adding tags. When tags are supported, this allows you to categorize your content in ways that make it easier for people to find information in your blog. In addition to this type of tagging, there Windows Live Writer make it easy for you to add tags right into your post. This kind of tagging assigns meaning to your post for services like Technorati to use in categorizing and marketing your content. It can also make it easier for your users to quickly add your content to social bookmarking tools like del.icio.us.
I hope this helps and I'm sorry for the delay. I moved the site to a new hosting provider over the weekend and the email notification on the forums is still not working. I didn't realize I had posts in the forums that were 2 days old!
Thanks for using metaPost!
Don