As I move the mouse pointer down the list of titles resulting from a search, a balloon with details about the title pops up at each title. I find this terribly distracting and would like to have an option for turning off this feature.

I'm currently running LimeWire Pro 4.13.2 under Linux.

Right click the cloumn header > more options > untick 'extended tooltips'.

AHAH! Many thanks birdy.

Ten thousand thank you's. That was my main question too.

That's terribly counterintuitive... please change it. I also would like to note that even for people who like the tooltips they don't work okay.
First of all, they always pop up under the mouse pointer, making it impossible to click on an item without moving the mouse away from the tooltip, possibly triggering a new tooltop (again under the mousepointer) when you accidentally move the mouse to the wrong item. This is the primary reason I've turned them off.
Secondly, if you actually want the information in the tooltip (most of the time it's useless) they don't stay visible long enough to be readable.
When you are dealing with rarely needed information that must be displayed for arbitary amounts of time, a dialog box is better suited than a tooltip.

The tooltips wouldn't be as intrusive if they were displayed only with the mouse pointer on a specific column. The "Quality" column would be good for this (IMO) since it's close enough to the "Name" to be convenient but not in an area where most people would normally be wandering the mouse pointer. And with it thus restricted, the tooltip could remain visible indefinitely.

If there are a bunch of identical or similar items in the Name column, I can see why a tooltip would be far more desirable than having to click to get a dialog box, then click again to dismiss it.

Of course tooltips can be useful sometimes, for example when a filename doesn't fit in its column. For example the Windows treeview control does this; open up the help for some application and find a topic with a long title to see how this works. Note that if you click the tooltip, it will still behave as if you clicked the topic; in other words, it doesn't block like those in LimeWire.