I was playing Diablo 3 these days and I found it's hard to read the name of the objects on the ground 'cause they are moving as I moving, so I wrote this small program to test my idea. (BTW, Diablo 3 sucks, not that big different from Diablo 2 and I'm wondering what is Blizzard doing in so many years...)
Here it is (it's using Java so you might need to allow it to run):
[applet code="MovingCaption" file="http://www.zhujunsan.net/wp-content/uploads/2012/06/MovingCaption.jar" width="480" height="640"]
The switch controls the refresh rate of the text.
When it's white, text refresh every frame; when it's black, text refreshes only if the next position is more than 30 pixels away. From my point of view, the "black" one might be seems a little lagging (actually not), but I can read the text faster than the "white" one. I think human can not focus on moving object, but only follow the object step by step, and that's why the lagging one is easier for human to read.
Well it's just my point of view, hope you have fun.
Here's the source code (using processing):