One of the main reasons for just requests(ask an fulfill) is to stop some topics been full of just requests.
There is a lot of posts that get deleted that are just requests or worth nothing related to the topic. I once cleaned up a topic and 80% was just requests an full of nothing.
I can see nigelmercier you are newby and have lots to learn how Sonsivri works, I don't know how you do it but when I sign in I click the new posts button at the top and look at all the new posts, This way you don't miss any requests or posting's.
Like janakfun said you have the search button which works wonders, It has never let me down and means your new here you may want to use it
You have lots to catch upon