This is what I mean by the highlights, in this case I was looking at a table of test results and wanted to see which ones were failed, without a highlight I had to strain my eyes and look at each word, with the highlight, it's like magic, the failed tests just pop out instantly!
So how do you turn this amazing feature on?
When looking at results/data simply right click and select 'Find/Highlight...'
This brings up a dialogue box, in my case I typed in 'fail' in the, ticked 'Whole Word' and 'Persist Highlight' and chose a red colour to display the cell with.
This will save the highlight for good, it can be removed later by clicking the X button in the same dialogue box next to the previously persisted highlight.
There is a bit of a bug I found with the highlight colour selector on OS X however, it seems that when you click to select a colour, the entire dialogue box disappears. The way to get around this is to click the down arrow on the colour selector and use arrow keys to select the colour instead.