Since many folks here are doing web startups that involve tagging (be or blog posts, photos, etc), this might be relavant. The use for tags is to cluster groups of photos together. But across users, tags are Inconsistent, somewhat defeating this purpose.<p>Lets take Flickrs tag example (most popular tags)<p><pre><code> photowalk2009, sp4449, pitchforkmusicfestival, worldwidephotowalk, skphoto, scottkelbyphotowalk, scottkelbysworldwidephotowalk, scottkelby, vihar, day199, scottkelbyworldwidephotowalk, scottkelbyssecondannualworldwidephotowalk, kelby, scottkelbyphotowalk2009, odori, photowalk, therebeastormabrewin, worldwide, riat, mefi10
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Notice that the "photowalk" appears so many different ways, where it should have been just one tag "ScottKelbyPhotowalk". This is just a example, but there are lot of instances where this happens with other tags.<p>Unifying the inconstant tags can be done in several ways. Automatically using world similarity, or allowing users to suggest tags that mean the same (then a moderator can go select the ones that validate them). Another way is picking a random tag and all objects tagged with it, and then examining the most common tags within that set (most likely the top N tags common to all of them will mean the same).<p>Just an idea to make your next app a bit more usable.