Backlinks Change Between WWW and non-WWW

[jk3210]

After staying relatively stable for some time, my backlinks dropped 90% yesterday. That's for mydomain.com.

However, when I check WWW.mydomain.com, the original number of backlinks are still there.

I thought Google treated www.domain.com / domain.com as the same thing?

[johnser]

I think it treats them as 2 separate domains.

Perhaps you have some internal links to domain.com and some external links to www.domain.com?