The SXSW festival in Austin has become something of a pilgrimage for social and/or location-based startups, hoping to follow in the footsteps of Twitter and Foursquare in using the event as a launchpad for success.
At the same time, the ease with which developers can create location-based services by tying into datasets and APIs from Google, Facebook, Foursquare and others is driving a burst of activity around location andapps, principally around iPhone and Android.
Here's a list of 20 apps that are part of this new wave of location innovation. All face the same three challenging questions: 1 How do they find an audience? 2 How do they make money? 3 If they're successful, how will they avoid being cannibalised by Facebook? Few have answers now, but this is nevertheless a snapshot of some of the more interesting ideas in the area.
Rather than ask what you're doing right now, Ditto prompts you to update your plans for what you're about to do, and then get recommendations from friends for restaurants, films or attractions, hooking into Facebook's social graph.
Launching just in time for SXSW, Yobongo is all about location-based messaging, promising to help its users "get started communicating with people around you". For now, it only works in New York, Austin and San Francisco though.
Shadow Cities (iPhone)
Location-based games are enjoying a second wind on iOS and Android, with Shadow Cities the latest attempt to turn real-world cities into massively multiplayer games. Hugely popular in its native Finland, it's launching globally this year.
Lonely Planet Audio Walking Tours (iPhone)
Travel firm Lonely Planet recently launched five walking-tour apps based on central London. Covering the West End, Covent Garden, the City, Spitalfields and the Southbank, they tie audio to location, plotting walks on Google Maps.
Flowd is another Finnish startup whose app starts with Foursquare-style check-ins, but then wraps music features around them. Users can follow bands' updates and tips, while uploading photos from gigs and entering contests.
Location-based dating has some challenges to overcome – specifically concern about stalking – but StreetSpark is one of a clutch of apps looking to hook singles up spontaneously. Its social matching process aims to ensure they hit it off, too.
Ask Around (iPhone)
Ask.com started life as the Ask Jeeves search engine, but its latest spinoff is a location-based conversation app. The emphasis is on questions and answers, with users able to tap into local knowledge when finding themselves somewhere unfamiliar.
Screach (iPhone / Android)
UK startup ScreenReach recently worked with Newcastle FC to allow fans at the club's stadium to vote for the man of the match using its Screach app. That's one use for Screach, but there are others – it can be used for coupons, content, voting and gaming.
Situationist is less about meeting friends than it is about meeting strangers in surprising ways. Users choose from a selection of scenarios, from impromptu hugs to angry flashmobs, and then wait for other users to detect their presence and carry them out.
My Star (iPhone)
My Star is a collaboration between UK developer Mobile Pie and operator Orange. It's a social music game where players level up their character and jam with friends. The location aspect involves plastering virtual flyers in real-world locations.
Like Yobongo, View is an app making its debut at SXSW that currently only works in New York, San Francisco and Austin. Its focus is on discovering information and tips about nearby venues, tapping into the Foursquare and Google Places APIs.
Love Clean London (iPhone/Android/BlackBerry/Windows Phone 7)
Even London Mayor Boris Johnson has his finger in the apps pie, having announced this week a new initiative called Love Clean London. Its app aims to encourage citizen activism, as people report graffiti and other "environmental crimes" by uploading photos.
Short Stack App (iPhone)
Australian pop-punk band Short Stack are one of the first artists with their own social location app on iPhone. It lets fans check in to gigs Foursquare-style to earn points as part of the app's loyalty programme, which can then be exchanged for rewards.
The name says it all: payasUgym is all about buying one-off e-passes to use gyms, currently across London. Its iPhone app takes the process mobile, allowing users to search for local gyms on a map, and then buy an e-pass there and then to use them.
Another startup hoping to make a splash at SXSW this year by splicing location with questions and answers. With Localmind users can see who is checked in to a specific venue via Foursquare, Facebook Places or Gowalla, and send them a question – with a points system to reward answers.
Broadcastr styles itself as providing "location-award audio and storytelling", and is making its debut at – you guessed it – SXSW. It lets people record audio clips and associate them to locations, for others to tune into when using the app in that spot.
RedRover takes a more niche spin on the idea of a location-based social network, focusing purely on parents. With a slogan of "make playdates on the fly", it helps groups of friends with children to arrange impromptu meet-ups, while finding child-safe locations.
Heyo doesn't revolve around locations, but around events – parties, meetups, sports and so on. It ties in with Facebook and Twitter to provide calendar notifications. There is a location aspect though, with the app identifying friends' events in the user's vicinity.
A lot of social location apps put their emphasis on partying, but there's arguably as great a need for business-focused apps too. Unsocial ties into LinkedIn to help people find relevant work contacts at events, such as conferences, including messaging features.
Hot Spots @ SXSW (iPhone/Windows Phone 7)
PR group Waggener Edstrom has its own SXSW app that aims to pinpoint the most popular events by crunching data from Foursquare check-ins. This idea of aggregating and analysing data from the bigger social location services is likely to fuel more apps in 2011.
That's our list of 20, now tell us what we've missed. What innovative and interesting location apps have you seen that you think have a shot at building a business? Which of the ones above do you think have legs? Join the debate by posting your thoughts.