The Highland Council Consultation Portal is a new and "easy way of reading and commenting on new and draft Development Plan documents" from The Highland Council.
One registers online at the link provided below.
This is different and additional to the current portal for responding to ordinary planning applications. This new one is only for consultation documents, so one needs to register for both of these if one wants to comment online. They may merge some time in the future.
Both links are permanently available on the Links menu on the left.