okay yes ITHs are crap and all. here's what they are, though
mainly you put the runes in the item of your choice, then you use the handy-dandy (not to mention evil, devious, and generally nasty) program to make all of the runes pop back out, freeing up every slot so you can use even more hacked items, like jewels. however, the new item doesn't have any of the bonuses that the runes give by themselves, only the runeword bonuses.