A who’s who of European technology entrepreneurs will be providing guidance and mentoring to a new generation of start-ups at this year’s Seedcamp. Founded by Saul Klein of Index Ventures and run by Reshma Sohoni, formerly of 3i and Softbank Capital, Seedcamp aims to build and support a community of European tech entrepreneurs, culminating in its main event in London this September.

The best-known entrepreneurs on this year’s advisor list are Niklas Zennstrom, founder of Skype, the internet telephony service, and more recently Joost, a web video provider; and Brent Hoberman of travel site Lastminute.com and, latterly, Mydeco, an online furniture retailer.

The rest of the advisors are all big names on the European start-up scene too, as founders of many of Europe’s largest recent tech exits. They are: Michael Birch of social networking site Bebo and Kevin Cornils of online marketing provider Buy.at, both bought by AOL earlier this year; Martin Stiksel of Last.fm, an online community of music fans for which CBS paid $280m in May 2007; Marten Mickos, chief executive of open-source database provider MySQL, sold to Sun Microsystems for around $1bn in January; and Jyri Engestrom of Jaiku and Tommy Ahlers of Zyb, mobile application firms acquired by Google and Vodafone respectively.

Alongside UK entrepreneurs who have yet to flip their companies for millions of dollars, and representatives from the big US tech companies who’ve been writing the cheques, this group will bring contacts, business advice and generally help start-ups at the week-long conference to “think big and aim high”.

Since May, Ms Sohoni has travelled led mini-Seedcamp events in Paris, Berlin and Kiev. But in spite of increasing numbers of new tech companies springing up in eastern Europe, she says London remains the main event. “We see the UK and London as a critical hub for start-up activities,” she says, especially for European companies with global ambitions.

Common technological themes among the entrepreneurs presenting across Europe so far include online and mobile gaming, personal finance applications, open source and variations on the “semantic web” – “the idea of using natural language to bring intelligence out of the information that’s out there”, according to Ms Sohoni.

But for those teams still applying to one of the 20 places at Seedcamp, she notes a preference of investors for business models based on transactional payments rather than advertising. “Everybody likes to put [advertising] up on their slide as a business model,” she said. “We were careful about that last year but are even more so now.”

Ms Sohoni also warns that almost half of last year’s applications came from social networking sites – none of which received investment.

“We are looking for globally applicable businesses that can grow beyond their local languages,” she says.

Seedcamp Week runs from September 15 to 19. The deadline for entries is August 10. The Financial Times is a media partner at the event.

The exodus of early Facebook executives continues. Six weeks after Facebook announced the departure of co-founder and technology guru Adam D’Angelo, the social network said on Thursday that Matt Cohler, one of Mark Zuckerberg’s first hires, is on his way out.

Well, not exactly. Cohler is leaving his position as VP of product development to become a general partner at Benchmark Capital, a Silicon Valley venture capital firm. But he will stay on at Facebook in an “advisory” capacity, whatever that means. 

Cohler’s not-quite departure is the latest evidence of the changes underway at a company that is trying to mature beyond its scrappy startup beginnings. Of the original, core team of executives that led Facebook up from obscurity to take on MySpace for the title of world’s biggest social network, only Mr Zuckerberg and his former Harvard roomate, Dustin Moskovitz, remain.

It’s not hard to understand why. It has been ten months since Facebook garnered its eye-popping $15bn valuation in an investment round with Microsoft, and the pressure to drum up the sales and profits necessary to justify such a high price tag remains intense.

Yet for all the work Facebook has been doing to develop its business model, it has little to show for it publicly. Over the past few months, the company’s PR operation has fallen largely silent, while the focus of internet buzz has shifted to other services like Twitter and Friendfeed (a Benchmark company).

There is little doubt that Zuckerberg and his new number two, Sheryl Sandberg, are hard at work on the business model needed to carry Facebook through the next stage of its development, perhaps paving the way for an eventual IPO. But there is also little doubt that Facebook isn’t quite the free-wheeling startup it used to be.

It has been more than a year since we flagged Twitter as the most buzzworthy social application in Silicon Valley. Thirteen months later, the micro-blogging site, which allows users to follow each others’ short online updates, has become an indispensible tool for the online cognoscenti who have gathered at San Francisco’s Moscone Center for this year’s Web 2.0 expo.

Jenn Van Grove, a social media consultant, says Twitter helps her follow the latest online buzz and keep in touch with hard-to-reach people. “If I need to get in touch with someone, Twitter is much faster than email,” she says. 

Ryan Kuder, a former Yahoo who is working on a new web startup, assured me that time invested keeping track of contacts on Twitter returns dividends.  ”People ask if you can spend too much time on Twitter,” he says. “I say you can’t spend enough.”

Sceptical journalist that I am, I signed up for Twitter in March of last year but never really got into the service. Intrigued, I dug out my Twitter ID and passed it along to Jenn, Ryan and a few other bloggers seated at our table inside the Web 2.0 blogger lounge. I have now been Twittering for all of two hours, and thanks to my new Twitter friends, I’ve managed to attract more than 50 followers.  Better late than never, I suppose.

Facebook’s users are bound to be excited by news that the social network is planning to roll out its own chat service in the coming weeks; Facebook developers, perhaps not so much.

There are dozens of developers offering chat applications designed to run on the Facebook platform. Facebook’s decision to get into the chat business for itself means those developers will now have to grapple with an 800 lb gorilla in the room, sucking up all the air

As revealed to reporters on Tuesday, Facebook’s new chat service looks to be a no-frills affair. The service doesn’t allow group chats, and users will only be allowed to chat with other Facebook friends. Still, Facebook’s decision to make its chat service a full-fledged feature of the site means that it will be in pole position to capture users from rival applications that sit on the Facebook platform.

The situation is reminiscent of that faced by developers writing applications to run on Windows in the 1990s. Back then, if a particular application market got big enough, the chances were that Microsoft would move in to try to capture it for itself. That is why Microsoft muscled its way into the highly profitable market for word processing and other office productivity software, where it was able to gain a huge advantage by tying shipments of Office to Windows.

None of the third-party chat applications on Facebook have met with huge success yet. But there are signs that chat could become an important feature on social networks as it has on the rest of the internet, where usage is widespread. AOL, for example, has said that close integration with its AIM messaging service is one of the chief rationales behind its $800m acquisition last week of Bebo, a Facebook rival.

In addition to its new chat feature, Facebook already has applications that let its users share photos, video, and other information with their online friends. The question vexing Facebook developers is, what other popular applications does Facebook plan claim for itself?

Mark Zuckerberg scored a coup on Tuesday by recruiting one of Google’s top stars to take the number two spot at Facebook, the fast-growing social network.

Among other things, Sheryl Sandberg’s appointment as Facebook COO will bring some adult supervision to a company that, for all the buzz and excitement,  manages every so often to remind the world that it is being run mainly by twenty-something computer geeks.

Sandberg, 38, graduated near the top of her class from Harvard College and Harvard Business School before serving as chief of staff to US treasury secretary Lawrence Summers during the Clinton administration. She joined Google in 2001, where she was responsible for developing the search giant’s wildly successful ad sales programmes. She also played an important role in launching Google.org, the internet group’s philanthropic arm.

Having captured the attention of millions of internet users, Facebook’s biggest challenge over the next year will be to deliver its own equivalent of AdWords - a technology capable of turning all those eyeballs into a reliable revenue stream.

Facebook tried to do just that last year with the launch of several new ’social’ ad technologies, including Beacon, a messaging service that broadcasts purchases made by users on outside web sites to their Facebook friends.  Mr Zuckerberg hailed the new technologies as a once-in-a-hundred-years innovation in advertising, only to see them overshadowed by a user revolt over privacy.

With Ms Sandberg on board, Facebook has an opportunity to move beyond this somewhat ham-fisted attempt and find a sustainable revenue model that takes advantage of the social connections between the site’s millions of users. There is no doubt that the raw materials are there. It may just take an experienced hand like Ms Sandberg to make things fall in line.