True power from the Semantic Web comes from interoperability - different information sources interacting and working together to provide a more coherent picture of the whole. Publishing data about people on the web is what FOAF does best: taking the information on those people and presenting it in a way that machines can understand it. However, if no one ever finds these files, there's very little use for them: after all, it's just as easy to create a page with an HTML description if no machine is ever going to read it.
For this reason, it's useful to make your FOAF file available to tools on the web which may want to get this data for some reason. There are a number of ways to make your FOAF file more commonly known on the web, and you can perform any number of them, depending on how interested you are in having FOAF start working for you.
- Use <link> tags in HTML pages to indicate your FOAF file - This method is the most common when integrating FOAF in a way that tools can understand it in your weblog or homepage. By adding tags along the lines of the following, you can tell tools where your FOAF file is, and which person in that file is "you":
<link rel="meta" type="application/rdf+xml" title="FOAF" href="http://crschmidt.livejournal.com/data/foaf" />
<meta name="foaf:maker" content="foaf:mbox_sha1sum 'd1235763342ad472a26e0cc3b2cc01268c98690
This is best for tools which work in the browser or based on your homepage, such as the FOAF Firefox Extension.
- Listing your file in a "FOAF Bulliten Board": The FOAF wiki offers a page for new participants in FOAF to list their FOAF file, called FOAFBulletinBoard. This data is exported as RDF, which can then be consumed by various tools. This is a good way to get your FOAF file seen by developers of FOAF applications, who use the wiki as their primary communication method.
- Adding your FOAF file to FOAF applications: Many applications which use FOAF offer the ability to add a URL to their service. By adding your file, you can ensure that your file is seen by that application, and maybe seen by others as well. Some examples are:G
- Give it to friends - There's no better way to get your FOAF file out than to have your friends add it to their own FOAF files. RDF allows you to define other "files" to look at, and this is the most common way of getting your FOAF data into other tools. One good way to do this is to list your FOAF file prominently on your homepage or weblog, possibly using the FOAF graphics to indicate its presence.
- Send it in email - If you have a client which allows you to edit the email headers, you can include an email header X-FOAF: http://example.org/foaf.rdf that indicates the location of your FOAF file. Tools which understand incoming mail may be able to use this header to find information out about you, helpful for whitelisting and other purposes.
Of course, there are many more ways to get your FOAF file out, from adding outgoing email headers to showing it on your business card. However, the services mentioned above are the better ways to get your FOAF file recognized by semantic web tools quickly.