If you want to view posts in more than one tag, use the following examples:

• http://www.paranoidangel.me.uk/blog/?tag=doctor-who,sja gives all posts tagged with either Doctor Who or SJA
• http://www.paranoidangel.me.uk/blog/?tag=doctor-who+sja gives all posts tagged with both Doctor Who and SJA
• http://www.paranoidangel.me.uk/blog/?tag=doctor-who,sja&feed=rss gives the RSS feed for all posts tagged with either Doctor Who or SJA

If you want to view posts in a category and tag, use the following example:

• http://www.paranoidangel.me.uk/blog/category/life/?tdo_tag=doctor-who gives all posts in the TV category and tagged with Doctor Who
• http://www.paranoidangel.me.uk/blog/category/life/?tdo_tag=doctor-who+sja gives all posts in the TV category and tagged with both Doctor Who and SJA (no or for this, you'll just have to search twice instead)