After purchasing ES for my main site, after only a few days with it running, there is a approximate 40% increase in daily postings all due to members being able to now efficiently find content quickly, the first time, thus posting onto it. Before, so many search queries weren't being returned due to the inefficiency of MySQL search. As a result, bugger the big board approach, I'm going to be installing ES on all my sites simply due to the fact it is showing a clear and significant increase in posting since its installation a few days ago, and my server stats aren't showing any increase in traffic to account for it. These figures have been quite steady for months, bar the obvious decrease for the holiday period. Obviously I will monitor this... though there is nothing new to account for such an increase in posting other than a vastly improved search capability. Just goes to show how one small improvement can dramatically change users actions when they can accurately find content.