Ask.com has joined Google, Microsoft and Yahoo search engines in their quest to reduce duplicate URL clutter by supporting the canonical URL tag. The tag tells search engines the preferred location of the URL to index when more than one site page has the same content.
Canonicals operate similarly to redirects for all URLs displaying pages with this tag. Site designers thus have more control to decide the pages search engines pick up, represent and index. Yufan Hu calls the move a "timely, relevant, and positive partnership between major search engines."