1. How does this experiment work?
   
   
2. Why use only emails?
   
   
3. Can I use google to find targets?
   
   
4. Can I send a message to more than one person?
   
   
5. I know a person to whom I'd like to pass the message, but I don't know their email address. Can I find out their email address?
   
   
6. What happens if the person to whom I sent the message refuses to participate?
   
   
7. Can I participate in more than one chain?
   
   
8. What's the difference between this project and a chain letter?
   
   
9. Is this experiment legitimate? Who funds this project?
   
   
10. Once the project is finished, will I be able to see the results?
    
    
11. Can I track the progress of my message?
    
    
12. The site's grammar: Why do you use them and their instead of he/she and his/her?
    
    
13. Is the chain on the index page real?
    
    
14. Is it really 6 degrees? Why would it be 6?
    

Your task is to move a message closer to a target person somewhere in the world. You can be involved in several ways. You may have received a message from a contact of yours asking you to participate by moving forward an already existing message chain. You may also start your own message chains trying to reach a range of targets. You must send all messages using our website. Collectively, participants link together to form chains, reaching from inital senders to our chosen target individuals.

If you received an email from a friend or acquaintance with a link then you need to follow that link. Otherwise, you can just sign up and start your own chains. We first ask for your consent to participate in the experiment, and then ask for some basic information about you to help us better understand how messages move through social networks. You will then see your target's photo and a short bio, and we will ask you which friend or acquaintance you wish to choose as the next person in the chain. Finally, we will send your contact a message from you, asking them to participate in the same way. This process continues until, hopefully, a chain reaches the target person.

Emails are easy to track. Because all messages are sent through our website, we can easily record their progress towards targets. Since not everyone uses email, we acknowledge that our sample will contain biases. However, nearly 600 million people now have home Internet access (see this report [pdf] from Nielsen//NetRatings) so the potential sample space is not small. Furthermore, since participants provide basic demographics, we can determine the biases contained in our sample at a later date.

No!!! The rules are that you can only send e-mail to people you already know. This means no cold calls: Please do not send e-mail directly to a target if you do not know them. The targets will get upset and will leave us! The kind of search our experiment is testing is a collective one. Participants have to rely on their fellow chain members to do their best to forward messages towards the targets.

Yes, you can send as many messages as you like for each of your targets. For each target, you must send your messages to different people. It's possible that for two different targets you might choose the same contact person, and this allowed. No one likes spam and we certainly don't like spam. Since you have to answer a series of questions about each person you pass a message to, sending large numbers of messages through our site would be a very, very slow process. Also, the format of each email is controlled by us (you can include a short message) so this wouldn't be good for spammers either.

If you know the person, and they know you, then you can ask them for their email address. You can even look it up. However, if you don't think they would recognize your name, then you should try someone else. The person you send a message to must acknowledge they know you.

If we haven't heard from that person in a certain period of time, we will send them a reminder email. Many people respond to these reminders and continue their chains. For a range of reasons, people don't always participate (roughly 35 percent do take part in our experience) and this is (partly) why we allow you to send as many emails as you like.

Yes. You can sign up for as many targets as you like (limited by how many targets we have on offer at any given time). You must send at least one email trying to reach each of your current targets before adding another target.

Chain letters are not directed at anyone in particular--their only object is to spread. Chain letters also generally contain some kind of message, whereas our emails don't. We are trying to determine how people can find each other in the world's vast and complex social network.

Yes, this experiment is legitimate. It has been fully reviewed and approved by Columbia University's Institutional Review Board, the university's official mechanism for authorizing all human subjects research. If you would like to check our status, the protocol number for this experiment is #02/03-566C (latest renewal 4 Dec 2002). The project received seed funding from Columbia's Institute for Social and Economic Research and Policy (ISERP) and is currently being funded by the James S. McDonnell Foundation (http://jsmf.org/). The principal investigator (Professor Duncan Watts) also receives general support from the National Science Foundation.

If you have asked us to send you results, we will inform you of all results that we publish, sending you a summary of the results directly and also links to any published articles. You can select this option on your My Small World page.

We are currently working on adding message tracking. When this feature is available, you'll be able to access it from your My Small World page.

The singular use of they is more common than many people think and has been around since at least the 14th century. We often employ it here to improve the readability of our questions, emails, and descriptions. A revealing discussion of this topic is provided here: http://www.editorscanberra.org/they.htm.

No, this chain is for illustration purposes only. The copyright owner of two of the pictures (Prema and Vijay) is "WHO / P. VIROT."

In our first experiment, we estimated that people are separated by 5-7 degrees (5 if the chain starts in the same country as the target resides and 7 otherwise). This estimate was determined using how often chains stop and the fact that successful chains (ones that reached their targets) had an average length of about 4. Since successful chains are more likely to be short (longer ones have a greater chance of someone not participating and therefore not completing), this average of 4 underestimated the `true' average chain length. To complicate matters, the average length of successful chains in Milgram's original experiment was 6 but when the loss of longer chains is accounted for, the `true' average length of chains comes out to about 8 or 9.

The number 6 is therefore not special. Moreover, many large networks can have a relatively small number of degrees between all nodes (less than 10, say). The key issue is that only some of these networks are searchable. In social networks, sufficiently motivated individuals can find each other using only their social contacts. People are not far apart and they can find each other.