There is a way but it's take some tinkering and might break something related to the list so this is without any warranties.
Create a new Discussion Board and create a new column of the type Yes/No and call it something like Sticky/Important. Set the default value to No
.
Open the site where the Discussion Board list exist in SharePoint Designer and navigate to Lists and Libraries
and find the Discussion list that you created and select Add new view
. Call it something like Admin or anything that you like. Do not set it as default view.
Now back in SharePoint, select the view you created and add the column you added in the first step and add it to the view and then add the column Edit (link to edit item)
. Scroll down to the Style
section and choose Basic Table
. This view is where you will be able to change the name for the discussion or make it sticky or not.
Save the view and then go back to SharePoint Designer, and look at the views, the default view for your discussion board should be called Subject
. Click on the view and select to edit in Advanced Mode
.
On line 33, there should be the listview GUID and some properties. Find the property called ReadOnly
and change the value from FALSE to TRUE. Save the update in SPD and head back to SharePoint. Now you should be able to edit the view Subject
, here you will change the sort order to first order by your column from the first step (Sticky
) and select to Show the items in descending order
.
Save the change to the view and create some discussions as a test. Check the Sticky
checkbox for one of the discussions and they should now appear on top.
This is my result. To the left is my default view on the discussion board, and the right is the custom view (Admin) that i created where you can see the "Sticky" discussion where created before several newer discussions.

But as i said, this is pure tinkering and might break, so test it thoroughly before you actually decide to implement it to your customer.