RSS Classifieds

I’ve been discussing the “RSS classifieds” idea (for lack of a better name) more with a few coleagues. I think the idea has merit.

The basic concept:

A rich RDF format is developed for specifying “I have something to sell”.
People that are selling can create this once, and register with search engines. Search engines pick look at the item, determine if its worth “accepting” into their system, and then post it for sale.

Why do I want this? Can’t I do it on EBay? No, you can’t. EBay, for all its greatness, is a closed system. Fortunately, for most sellers, EBay is currently the largest online marketplace, so its a safe bet. But, if you want to advertise your forsale item elsewhere, you have to do that manually – reposting your data into each system separately. You probably have to register on each system separately, etc etc. Its a real pain in the neck. And, in exchange for you locking in exclusively to EBay, EBay also takes a small fee from you!

OK. So, moving on. What we need to have such a system:

1. A format to specify for-sale items in RDF and RSS
2. Search engines that recognize the format. An ability to make sure that search engines “stay fresh” with the current status of the item

Well, thats it to get to phase I.

But, there is more. One really handy thing about EBay is its rating service for users. With RSS, I think this is reproducible in a distributed way. Lets say Bob and Charlie are about to engage in a transaction, where Bob is selling to Charlie. After the transaction, Bob puts a review of Charlie into his feed, which says “Good”. Charlie puts a review into his feed which says “Bob” was “Bad – late with payment”. As Bob and Cherlie enter into many transactions over time, each will be reviewed by others many times. These reviews can be found by search engines, and an overall composite score can be generated for each user – in effect replicating what EBay has done. Of course, as will everything on the web, we’ll have to take some time building anti-Spam features. We don’t want Bob to be able to boost his ratings by just creating lots of fake reviews of himself. That is probably solvable with a few heuristics, much like what search engines use today. The harder case is the case where Bob wants to maliciously accuse Charlie of being “Bad”. These may be solvable by using anti-spam techniques and also by allowing Charlie to post his own “Review-rebuttal” within his own feed. Lastly, this mechnism has problems with individual changing their reviews over time. Sure, Bob initially gave Charlie a good review. But after Charlie gives Bob a bad review, Bob goes and changes his review of Charlie to say “Bad”. It may be that a webservice is in order here for verifying the authenticity of reviews.

One other interesting point is anonymous email. I don’t think blogs will be using open email addresses forever. Once the spam bots figure out how to parse these little gems, we’ll all be spammed in our mailboxes. Plus, we really don’t want the general public to browse and see that Bill Lee is selling his collection of fancy dolls. So each forsale item that gets posted in RDF/RSS format may want to include contact info which goes through a one-way email anonymizer service. Many (most?) of the classifieds services online today already provide this. Craigslist is a great example.

From what I’ve seen, nobody has really done this so far. (Let me know if you’ve seen otherwise) I’m not sure why. Maybe there is no money in it. Also, I think the level of complexity in RDF for this type of thing is substantially more complex than anything in any of the RSS specifications today. Today’s RSS is about as simple as it gets.