Twitter’s new Local Trends function on Twitter.com is basically meaningless. It’s full of spam (just as the global Trending Topics is) and really isn’t all that interesting because: 1. lots of the same trends go across the limited number of places Twitter is offering right now; and 2. there is no context for the user other than millions of other people in their city or country tweeting. We held off on writing about Local Trends until today because until Tuesday only about 1% of Twitter users had Local Trends enabled (not sure if it is 100% now, but lots of people now have it enabled) and second, the API function related to Local Trends wasn’t turned on either until the last 24 hours or so. As with most things in the Twitterverse, the API is where it’s at, and now Local Trends can really get interesting.

Twitter’s API team turned on two calls – Local Trends/available and Local Trends/location. While Twitter is still apparently building out the places that they can offer trends around, this API call will allow developers to go beyond geotagging of tweets (which will discuss below) and map out trends and search parameters inside of their applications. One interesting line in the API documentation says that Local Trends are “an array of “locations” that encode the location’s WOEID and some other human-readable information such as a canonical name and country the location belongs in.” We read that as saying that Twitter is using a mix of ways to determine a user and a tweet’s location, and not just relying on lat/long. Obviously, there could be many uses for this.

One use that comes to mind is a “breaking news” application that could push out notifications to users when a local topic starts to trend. Another could be a map-base app that shows heatmaps of trends, for instance, which trends are hot or not in different areas of a state. Check-in apps (i.e. Foursquare, Gowalla, Yelp) could also use this data to compare check-ins across a trend – so for instance, on New Year’s Eve, users could drill down on the “Happy New Year!” trending topic to see where people mentioning that trend in their city are checking in, which could be a good indicator of where the best party spots are. The possibilities are not limitless, but there are a lot of ways this data can be used.

That said, there are three major drawbacks to what is in place right now. First of all, spam is a huge issue that right now often accounts for 50% or more of trending topics on Twitter, and we’ve noticed the same thing happening with Local Trends. Twitter needs to figure this out, and needs to figure it out fast, or the entire concept of trends is going to be worthless. Secondly, Twitter’s attempt to get users to geotag their tweets has been to all reports nearly worthless – almost no one is turning this option on, so the accuracy of Local Trends has to be called into question we think. Finally, while Local Trends (if accurate) is interesting in a discovery kind of way, it really isn’t all that relavant to the user because right now there are no filters in place to see what’s trending locally among your local followers or people you follow. Foursquare quickly figured this out when they added friend leaderboards in addition to city mayorships soon after they launched last year, and major apps that figure out this kind of filtering will have a hand up on their competitors. We will be closely monitoring which apps integrate Local Trends, and more importantly, what they do with this new feature.