So you've got your blog set up with tags. A neat way to expand this is to offer RSS feeds for each of your tags. Visitors can subscribe to these feeds and be updated when any new entries are posted that are tagged with that particular keyword/subject.
You'll need to make another alternate search template. My template for an RSS 1.0 feed is at "Keyword RSS Template" here.
Link to it in your templates with <$MTCGIPath$><$MTSearchScript$>?Template=rss&IncludeBlogs=<$MTBlogID$>&SearchField=keywords
&search=<$MTSearchString$> where "rss" represents the name of your template in mt.cfg (for some reason, I found that putting the items in the URL in a different order produced a feed that didn't display properly as RSS in the browser; however, this order works). I link to it on each tag's page. If you're linking to it elsewhere, replace <$MTSearchString$> with the template tag that you use to call the particular keyword tag. I also created an Index of Tag Feeds to list all the available feeds. I did this by hacking the code for the tag cloud page; this requires PHP. I'm not sure why there's a blank tag at the beginning or why the feed for it is empty. I'll have to look into that further.
&search=<$MTSearchString$> where "rss" represents the name of your template in mt.cfg (for some reason, I found that putting the items in the URL in a different order produced a feed that didn't display properly as RSS in the browser; however, this order works). I link to it on each tag's page. If you're linking to it elsewhere, replace <$MTSearchString$> with the template tag that you use to call the particular keyword tag. I also created an Index of Tag Feeds to list all the available feeds. I did this by hacking the code for the tag cloud page; this requires PHP. I'm not sure why there's a blank tag at the beginning or why the feed for it is empty. I'll have to look into that further.