I haven't seen an option to stop certain words being searched for. such porn words and such, for each of the other categories. maybe this is could be a new feature. The filter doesn't seem to be working too well, works on some sites, others not so well.

>>"I haven't seen an option to stop certain words being searched for. such porn words and such, for each of the other categories. "

A (recursive) DNS service like OpenDNS cannot filter content delivered over another protocol; OpenDNS cannot (and should not) see what queries you're sending to another service and the results returned. You cannot filter specific search engine results with the OpenDNS service, but you can block access to the search engine by domain name through your Always Block list or by blocking the Search Engine category.

>>"The filter doesn't seem to be working too well, works on some sites, others not so well."

You can open a ticket with our support team to help get your filtering working properly:
https://dashboard.opendns.com/support/

Also, it's possible that the domains you're requesting on your network are not tagged yet and thus cannot be filtered without the use of your Always Block list:
http://community.opendns.com/domaintagging/
https://dashboard.opendns.com/settings/

Also, I suggest you read through the following:
http://forums.opendns.com/comments.php?DiscussionID=11313
http://forums.opendns.com/comments.php?DiscussionID=10433