Canonicalisation is an issue most SEO-involved site owners are used to dealing with. Or are they? Canonicalisation may be a problem that’s been around for a long time, but some site owners may still be struggling with some of its hidden complications.

There are a few canonicalisation problems that are easy to deal with. It’s not hard to choose the updated version of a page, or to sift through categories to make sure the same page hasn’t got two URLs. Some of the other complications are less easy to spot.

Session tracking URLs. If you’ve got affiliates sending you traffic, you’re probably measuring their efficacy with a URL parameter. Unfortunately, session IDs create duplicate pages

Mistaking templates for canonicalisation. Some bloggers get into trouble when archiving blog posts. Make sure your content isn’t displayed on multiple pages within categories

• Multiple home pages. It’s amazing how many sites still have old URLs for home pages floating around. Check for ’/index’, ‘/home’,’ /default’ and other homepage variants

Once you find the problem areas, you need to determine the canonical pages and redirect or index all other versions. Canonicalisation problems aren’t always easy to spot.

It’s a big enough problem that if you suspect your site has serious canonicalisation issues, it’s a good idea to consult someone about it, and you can discuss this with us at a single version of a page on the index is a basic organic search engine optimization practice. If your professional SEO services don’t cover canonicalisation issues, it’s time they started.