On the UNITAB site quite often you will see a jockey listed
in colour (yellow) what does this signify?
None of the other TAB/Betting sites have this.

That simply means they are a late riding change or an addition to the riders listed in your form guides. Often these late riding change horses seem to get up at big odds. I had a look at it recently and simply betting level stakes on each of them (no matter what the horse's form) produced a handy profit over a week. Certainly not suggesting that would work long term though.

Hi Sportz,
Interesting analysis, I had gleaned the same on perusal of some two years
of past performances:-
15/02/03 Bendigo race 4 No 1 Traditional Vain $45.801st
Bendigo race 9 No 9 Traditional Girl $11.101st
16/02/03 Sandown race 3 No8 Sesemann $16.501st
16/02/04 Taree race 3 No10 Kaminari ($9.40)2nd
16/0703 Flemington race 6 No10 Achieved ($12.10)3rd
Grafton race 1 No 17 Totally Diamonds($14.00)2nd
23/10/03 Kyneton race 5 No 7 Maxisherer ($7.40)1st
The foregoing were taken at random(excuse the pun)
Maybe a system here
Anyone with a database that can throw up some
results!