Every user of Yenta runs their own copy. Yenta uses your web browser as its user interface. Just start up Yenta, point your web browser at the right URL, and you're now running a private web site on your own computer that only you can talk to. Want Yenta to look different? Just change your browser settings.
Yenta automatically deduces your interests from your files. You tell it which files to scan, and it computes a description of what they talk about by which words appear in them. You can also tell it to ignore things it finds that you aren't really interested in. Because Yenta uses your own files, it doesn't make you fill out long questionaires, or pick a few keywords from a list, or remember to do this if your interests change. It's all automatic.
Yenta never transmits information about your interests to a central place. Other matchmakers require that you submit all your information to their central server. But then you have to trust them with your data -- and even if they have good policies, crackers or subpoenas can make those policies irrelevant.
Yenta searches for other, like-minded Yentas all over the net. Instead of trying to match your data with someone else's at a central server, each Yenta communicates with other Yentas it sees on the network, and asks them for word-of-mouth referrals to Yentas that might be better matches. All communications are peer-to-peer, between cooperating Yentas, rather than client/server, as in most systems. And the data is carefully protected, so even the Yentas that get asked along the way can have only a hazy idea of whose data this really is.
Yentas form clusters when they find others with common interests. Your Yenta can be potentially a member of many clusters -- one per interest -- and these clusters form dynamically as Yentas discover each other and figure out their similarities. Yentas are not mobile and do not move around -- this keeps your data on your machine, under your control. Instead, each Yenta uses the network to talk to other Yentas it finds on other machines.
These clusters are the basis for messaging. When you send a message to an individual user of Yenta, or to a whole bunch of them that share an interest with you, these clusters are where your message is going. If two Yentas seem to have a very close interest, their users are informed, so that they may be introduced to each other.
You can build a reputation by having other people agree with things you say about yourself. You can make any number of statements about yourself, and others can cryptographically sign those statements if they have reason to believe them. Third parties can use these statements to evaluate your reputation: will you spam them? are you really a doctor? do you actually work for the company you say you do? And you can do the same when looking at other people's reputations.
Yenta runs forever. Once you start it, Yenta runs until you shut down your machine. It's constantly trying to find other good matches, even when you're off doing something else and not looking at it. And it saves its data to disk at regular intervals. When you boot your machine -- or even if your machine unexpectedly crashes --- just start up Yenta again, and it will read its stored data and keep going where it left off.
Yenta assumes you're permanently on the net. If you use a dialup connection and are rarely connected, Yenta may not work very well for you -- although it will work a little. Later releases may remove this limitation. (It's expected that pretty soon, permanent net connections will be commonplace for everybody.)
[ All this data flying around sounds scary! Why is Yenta safe? See the next page. ]