Frayed Abomination Stitchings were magically enhanced thread used to hold together Abominations. They were used as an ingredient in numerous quests for rare and valuable magic items, but seem to have lost their magical properties as an ingredient.
Unless you were a completionist, there was virtually no use for this item. As of Patch 3.0.8 they still dropped from the above mentioned monsters within Stratholme, usually between 3-6 per run. However, they could not be sold to a vendor. Until Patch 4.3, they were still useful if one was attempting to gain Insane in the Membrane.
Patch 4.3.0 (29-Nov-2011): Frayed Abomination Stitchings do not bind and are now poor quality, thus making them able to be vendored. Removed as a quest objective.
Patch 1.4.0 (2005-05-05): Frayed Abomination Stitchings are now considered to be uncommon items.