If the site admin wants to increase participation consider turning on some of the other commonly used interactive vBulletin board options.

The thanks button is very popular (let's posters know their comments were read and liked, there is a reason most all platforms utilize those "like" options, people post more when they get that obvious positive feedback). The current reputation button is nice but too discreet and probably not used nearly as much as a "like" button would be.

And since there are LOTS of sections that are hard to track, maybe turn on the features that notify posters when a post is quoted/liked or their name is mentioned with an @ sign etc... That makes it easy for returning visitors to respond to posts they might not otherwise see/notice, plus allows posters to "call out" to specific posters to get their opinions on a topic or bring them into a conversation.

But if the various notification options are turned on please make sure the default is NO email notification, else the board members will go nuts when their mail boxes are suddenly flooded.