Developer forum

I would probably use items instead of Forum, but if thats not an option then you can use this "workaround"...

You could register a dummy module, e.g. ForumSearch, and configure the search part. That will make it possible to use the Search, weighted module to search in forum messages (new settings will be available in the search module).

http://developer.dynamicweb.com/documentation/for-developers/dynamicweb-custom-modules/integrating-with-search.aspx

Something like this...

1) MODULE

Name: ForumSearch
System name: ForumSearch
Enabled: true
Paragraph module: false

2) MODULE -> SEARCH SETTINGS

System
Database:.
Item table: ForumMessage
Item query parameter: ThreadID
Category table: ForumCategory

Category fields
Id: ForumCategoryID
Name: ForumCategoryName

Item fields
Id: ForumMessageID
Category ID: ForumMessageCategoryID
Heading: ForumMessageName
Date: ForumMessageCreated

Search
Search in: ForumMessageName,ForumMessageBody
Body text: ForumMessageBody

Publication
Active: ForumMessageIsActive