Cobwebs were a embossed decoration found on a few different whiskey bottles from the early 20th century. Witness the picture of the Spiritus Frumenti bottle in the attached photo - this is a Prohibition-era bottle.
Your bottle however seems to have a decoration meant to imply cracks - perhaps cracks in ice? What you need is to find an example with a label; there lies the only path to finding out what product was contained within.
Sorry to say this bottle does not have much value, but I can say that interest in 20th century bottles is growing. A market for such glass still is limited.
The O-I mark on the base indicates Owens-Illinois Glass Company which had plants and various related companies around the US. This mark was used during the period 1929 up until 1954.
If it contained alcohol, and it may very well have, then it would predate 1933 since legislation after that time required embossing, "FEDERAL LAW FORBIDS SALE OR REUSE OF THIS BOTTLE. See my web page on this topic for more info: http://www.antiquebottles-glass.com/learn/federal-law-forbids-sale-or-reuse-of-this-bottle/