Symbols?
 

What are the pilot arms with a thumbs up mean when they are in the box of the thread please?

Atishoo,

I think this is a thread rating, ie. people voting on how good a thread it is. So a thumbs up means it's been rated as a good thread and thumbs down is bad etc. And I think the number of the stripes on the sleeves corresponds to the number of stars people have given it. At least, that's what I've understood it to mean from holding the cursor over the symbol and checking FAQ but please feel free to correct me if I'm wrong.

JSL