Sparks are set to fly this week as the tech world’s uber-nerds descend on California for two conferences designed to kick start Silicon Valley’s next success story.

At TechCrunch 50 in San Francisco and Demo 08 in San Diego, small technology companies with big ideas will pitch for cash prizes and the attention of investors in Dragons’ Den-style competitions.

The companies and products on show are yet to be released, but rivalry between the well-established Demo event and its upstart rival TechCrunch has already spilt over into acrimony and accusations of impropriety.

Michael Arrington, the influential and opinionated tech blogger behind the TechCrunch blog and conference, has vowed to kill off Demo, which is now in its 17th year.

In a series of attacks in his blog and in interviews, he has accused his rivals of running an outdated and unfair selection process. The $18,500 fee Demo charges participants amounts to payola, he claims, and cuts out fledgling companies that cannot or will not pay.

“Demo needs to die,” Mr Arrington said. “It clearly involves pay to play, and what we’re offering is better.

"If you are going to parade out a bunch of start-ups on a stage that paid you $18,500 each, you simply can’t say they’re the most qualified companies to be at the event."

TechCrunch 50 does not charge companies taking part in the core event, but away from the main stage, companies can pay to demonstrate their products in an area called the DemoPit. The event also raises money through sponsorship from venture capital groups and big technology companies including Google, Yahoo! and Microsoft.

Chris Shipley, Demo’s executive producer, said that the charges had never been hidden and that plenty of start-up companies were willing to pay. She accused the TechCrunch 50 organisers of limiting the options for technology entrepreneurs by scheduling their event to coincide with hers.

“TechCrunch set its sites on Demo and has been lobbing missiles our way ever since,” Ms Shipley told the San Diego Business Journal. “By putting TechCrunch50 up against Demo, TechCrunch has created a challenging dilemma for the best start-ups.”

The former TechCrunch blogger Duncan Riley agreed that animosity between the two events may not be in the best interests of the companies they are designed to promote.

“If they were serious about putting start-ups first, they would be focused only on creating more opportunities for start-ups to be discovered, and they’d allow their event to stand on its own merits without the need to constantly trash talk the opposition,” he wrote on his blog. “Are we not better off as a web community having both Demo and TechCrunch50?”

But Robert Scoble, the technology commentator and former chief blogger at Microsoft – and an unpaid judge at TechCrunch 50 – said that press and PR interest seemed to be shifting towards TechCrunch, in part because of the power wielded by Mr Arrington.

“If you are in tech PR you do not want to spurn Mike Arrington,” he said. “Arrington has thrown out stories from companies that let other blogs or journalists go out with news first, so they know there’s consequences for not playing Mike’s game.”

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