We all have one: It’s that thing that’s been collecting dust in your closet since the mid 90’s. You know it has to be worth something, but you’re worried that posting it on eBay will garner a whopping 99 cents (plus shipping, if you’re lucky). So it continues to sit. Ztail wants to put an end to this problem, and is launching a revamped site that it hopes will serve as pricing guide for everything under the sun.

Conceptually, the site seems like a mix between Antiques Roadshow, The Price is Right, and eBay. To post an item for appraisal users can either enter a description manually, or they can search through a database of over 1 million products provided by Shopping.com that contains default photos and descriptions (users can modify these if they wish). From there, the item is added to Ztail's "Get Worth" pool, which will present the item to other users and ask for their opinion. Sellers can also create a Ztail widget, which can be embedded in blogs and social networks to collect opinions of friends. After establishing a price, Ztail allows sellers to quickly sell an item on eBay using pre-defined templates.

Prospective buyers can peruse the listings to get a feel for how much each item is worth, which also makes Ztail something of a Kelley's Blue Book for just about anything.

The site serves both as a tool and a competitive (and potentially addicting) game. As members evaluate the worth of items, they can establish a reputation score based on their accuracy, which is determined by comparing each user's appraisal to the average. Members can enhance their accuracy score by linking to past eBay auctions, craigslist listings, or store prices to validate the prices they have suggested. This feature is where the site's real potential lies - if it can establish a hardcore group of professional appraisers for each category, Ztail could become an authoritative resource instead of a casual guide.

Ztail has a great idea, but it's going to be hard to pull off. Until the site can establish a sizable and credible user-base, prices are going to be highly variable and the site won't be much of a destination for anyone. That said, the market could really use a guide for "random stuff". Ebay works well enough for easily-identifiable products like electronics, but for everything else sellers are at the market's mercy.