SEO Extension – Controlling what search engines use for a specific item/page

I have just added the following to the Steve Bisbey page (where I was adding a picture). Interesting task - you have to "imagine" the reality of countless searchers! Any comments, reverend Editor ( :-) ) :

#seo:
|title=Steve Bisbey

|titlemode=replace

|keywords=Bisbey, Bisby, TIR, Traumatic Incident Reduction, PTSD, Post Traumatic Stress Disorder, handling trauma, prepcheck, unblocking, deblocking, incident reduction

|description=Obituary and short biography of Steve Bisbey, who was a mental health practitioner and author resident in the London Home Counties.

That does not quite duplicate what I wrote - Any one can see what I actually wrote (perhaps only if logged in) by pressing edit for the last section of the page, and then pressing cancel when they have looked.

What does |titlemode=replace do?