Innovators and trendsetters are heading to Texas for a technology festival renowned as a springboard for Web sensations such as Twitter and Foursquare.

Startups featuring new ways to mix mobile devices with social networking, shopping, geo-location, or augmented reality will be vying for the hearts of tech-savvy attendees at the South By South West Interactive event (SXSW).

A half-dozen "startup buses" loaded with software wizards set out days in advance for the Austin, Texas, gathering with a challenge to create winning technology companies by the time they arrive at the SXSW opening on Friday.

"It's a crowd that influences technology; that enjoys learning about it, talking about it and sharing ideas," said Scott Lahman, chief executive of mobile social messaging startup textPlus. "There is a mindset at SXSW to figure out what the next big thing is and then spread the word."

Group text messaging startups will be hot properties, seeking to be the most popular way for people at SXSW to swap discoveries, news, opinions and party venues with selected circles of friends.

TextPlus claims to be the biggest and fastest growing such startup in a category that includes Beluga, which Facebook snapped up this month.

"Group texting makes texting more interesting," Lahman told AFP. "It is like creating a private little chat room for mobile text messages."

TextPlus puts a social spin on group text messaging by letting users create profiles and groups based on interests or other topics.

Lahman estimated that about 25,000 themed text groups ranging from fans of pop star Justin Bieber to fans of World of Warcraft have been created at textPlus.

The slightly more than three-year-old service handles about 33 million text messages daily. The free texting service is advertising supported.

"There has been this social texting meme going on and SXSW is going to be the next battleground," Lahman said.

SXSW will teem with new software or services that let people share anything from pictures and videos to favorite restaurants and spontaneous party venues using smartphones or tablet computers.

"Sharing just seems to be enormous," said Richard Bullwinkle, chief evangelist at digital entertainment technology company Rovi. "We are social animals and want to figure out how to share with people who are relevant."

The interactive portion of SXSW, which is followed by a music and film fest, opens Friday with a presentation by SCVNGR, a mobile social gaming startup that factors player location into challenges and rewards.

"There is an evolution in geo-location," SXSW producer Shawn O'Keefe said.

"You are seeing an extension of geo-data, augmented reality... you've got a mobile device and you are able to pull in a lot of information about what is around you and who is around you."

He described SXSW as "ground zero" for social media, with Twitter being catapulted to glory at the festival in 2007.

With Twitter playing key roles in political upheaval in the Middle East, a lot of SXSW sessions will be devoted to using social media tools to catalyze social change, according to O'Keefe.

Speakers at the event will include the founder of 4Chan, a controversial online message board where anonymity is sacrosanct.

"It has been described as the bowels of the Web, but there is a lot of powerful stuff there as well," O'Keefe said of 4Chan.

The array of talks and startup launches at SXSW verges on overwhelming.

The powerful concentration of technology taste-shapers attracts major players in the industry.

Microsoft plans to launch its new Internet Explorer 9 Web browser at an SXSW party on Monday and events are planned to promote Google-backed Android software for smartphones and tablets.

Blackberry maker Research In Motion will host a shindig to show off its PlayBook tablet computer, and Apple will reportedly set-up a temporary store to sell the new iPad.

Sony will host a PlayStation gaming lounge where SXSW goers will be able to get their hands on eye-popping 3-D titles for its videogame consoles.

"SXSW is such a big deal in the technology world because it has an unjaded youth to it," Bullwinkle told AFP.

"People love the face-to-face interaction and intimacy from meeting like minded creatives," O'Keefe said. "These are geeks who are changing the world for the better, and not necessarily for the money."