We took some time, but here it is: Dynamic404 has hit version 1.0.16, bringing various fixes but most importantly Joomla! 3.0 compatibility. Now you can use Dynamic404 to improve your SEO under Joomla! 3.0 as well!
Dynamic404 is an extension that replaces the default of Joomla! error-handling. By default, it simply replaces the error-screen - you know, the ugly looking red box of Joomla! - with another ugly looking red box that lists a couple of search-abilities for the user: It lists a couple of page-suggestions for the user to click on, and it lists a link to the search-page. Nothing special.
But the list of page-suggestions is actually what Dynamic404 is about: Dynamic404 takes the current URL (that gives the 404-error) and searches the Joomla! database for possible matches. Those matches are shown to the user. But you can also configure Dynamic404 to automatically redirect to the match with the highest percentage! This way, your users will never face a 404-error, but will be redirected to the right page with a proper 301-error. This also counts for search engines - therefor Dynamic404 greatly improves your SEO.
With the new version, we have made Dynamic404 compatible with Joomla! 3.0. We have put a lot of work lately in moving code from the specific Dynamic404 scripts to generic classes, that are reused across various of our extensions. So instead of having just Dynamic404 compatible for Joomla! 3.0, we have made all our Joomla! extensions compatible with Joomla! 3.0 plus provided a framework that allows us to quickly update in the future (yes, we know we're running very late with our Joomla! 3.0 compatibiility).
Read more on the new features here.