Mashup Guide

"Machine tags" (see Flickr: Discussing Machine tags in Flickr API) have been introduced into Flickr as generalization of things like geotagging. Machine tags are also known by many as "triple tags". These are tags with a specific syntax aimed primarily for "machine consumption" (that is, by programs) and not directly for display to the typical end-user. You can use machine values to store extra data elements for a given photo. I think that it's fair to say that most important example of such data has so far been the latitude and longitude associated with a photo. So important that Flickr ultimately introduced specialized functionality to handle this data, to take that data out of the realm of having people just shoehorning that info into tags.

I'd really like to know what uptake there has been on machine tags. I was hoping to be able to do searches for namespaces in use — but as I document below, I don't know how to formulate a query to do so.

Some kinks have been fixed in the Flickr machine tags:

• If you look at http://tinyurl.com/2vyrgv — you'll see that yws-flickr : Message: bug with searching for machine tags? has been fixed.

Some outstanding issues remain:

• missing negative values and decimals in the machine tag API. See yws-flickr : Message: Re: Machine Tag Bug – missing negative values and decimals?. When I do the a query for my pictures that use the geo: machine tag name space and ask for the machine tags, I get the "-" and "." stripped out. (I confirmed the problem on March 11 but as of April 19, I've no seen any resolution.)
• no response to yws-flickr : Message: Re: Ladies and gentlemen : Machine tags. I'd love to have a whole set of query functionality, including being able to look up all domains in use. I know about "geo" but what others are being used — and with what frequency? For instance, we can pull up all the geo: machine tags by searching for "geo:" with the API call. See http://tinyurl.com/yt5k2f You will >500,000 photos under that domain. I tried variants on "geo:" to try to pull up all machine tags ("*:", "*", "*:*") but I couldn't find any that would get me all the machine tags….

What are the equivalent of machine tags in other systems? What to look at:

• bobdc.blog: All Your Google Base metadata taxonomy are belong to us and Google Base Help Center – What is an "attribute"? in Google Base.
• I also vaguely remember something about attributes in Amazon S3 that might be related to machine tags. (The connection is probably vague.)