Agreed its not going to be the only metric, but it's gotta be one, 0 words is as shallow as it gets so it's there in the sauce for sure.
If I go down to 50 the ratio drops considerably. This looks more accurate, a thread with 100 words or 50 and below looks a lot different in the browser than numbers in a table.
The posts below 50 words are no more than a few sentences, so not very 'deep'. They dont appear to be getting any traffic and are years old too so might as well make them vanish and see what happens.
You say it's not about words but i skipped all the Pandas until I stupidly reduced forum posts per thread page from 25 to 10 to see if page speed increased. The unaware side effect was spreading my content 'thinner'. 5 days later after a deep crawl Panda 2.4 released and i got dumped.
Thanks for both your input.