Dopplr, one of the darlings of the early adopter crowd, announced an all-star roster of angel backers today.

A social network primarily aimed at business travellers, Dopplr informs its users when serendipity delivers themselves and their frequent-flier contacts to the same city.

Its newest shareholders are a suitably globe-trotting and glamorous group. They include Thomson-Reuters chief executive Tom Glocer; Tyler Brûlé, founder of style magazines Wallpaper* and Monocle, and an FT columnist; Esther Dyson, formerly of Cnet, who announced her intention to invest in Dopplr in a Wall Street Journal article some months ago; Joshua Schachter, whose geek-friendly bookmarking service, Del.icio.us, was bought by Yahoo; and Lars Hinrichs, founder and chief executive of Xing, the German business networking site.

Dopplr declined to say how much it’s raised, instead focusing on the value of having such prominent evangelists for its service.

Those that get Dopplr, love it – for its design, its attention to detail and its easy integration with other sites such as Facebook. Those that don’t – which apparently includes paidContent blogger Robert Andrews, who calls the service “weird” – remain to be convinced that Dopplr’s main function – telling people where you are going – has broad appeal as a standalone site.

Also participating in the round, as a private investor, was Saul Klein of Index Ventures. Mr Klein’s other contribution to the startup community is Seedcamp, a conference for tech entrepreneurs which today debated two topics germane to Dopplr’s position: whether a business is worth backing as a “feature” which is set up merely to be acquired, and whether to take funding from venture capitalists.

Kevin Cornils of Buy.at, who also sold his online marketing service to AOL, said a larger, more fully developed company gets a better valuation. “The only thing to hold against AOL’s offer were our standalone plans,” he said, such as raising more money or making an acquisition.

Bebo’s founder, Michael Birch, noted the preponderance of feature sites in Europe and Silicon Valley that are “built to flip” – often to Google at a rate he pegged at $600,000 per employee.

The Seedcamp panel, which included the founders of Plazes and Jaiku, was generally appreciative of VC funding. Martin Stiksel of Last.fm said: “If you spend your own money, you could strangle your own business by being too prudent and tight… Spending someone else’s money is easier than  spending your own.” (He meant this as a recommendation.)

Mr Birch was more blunt: “VCs can be your friends and they can be a pain in the arse. It depends how your relationship goes.”

For now, Dopplr still feels like a (really useful, elegantly executed) feature rather than a complete site. But perhaps having a diverse group of angel backers - instead of the pressures of a VC - will give it the space to find a sustainable source of revenue.

Move over Silicon Valley. New York’s Silicon Alley is a Web 1.0 relic. And Cambridge’s Silicon Fen is just SO pre-crunch. Now Silicon Roundabout is staking its claim as the new tech start-up hub of the moment.

Previously known as the busy junction where London’s Old Street meets City Road, Silicon Roundabout is not the most salubrious of locations for budding entrepreneurs. But a coalescence of young web and tech companies in EC1 dates back to dotcom days. Alongside cheaper rents and a surfeit of bars, tapping into that experience is part of the area’s appeal for many of its newer residents.

Many will be hoping to follow the example of local hero Last.fm. The online music community was bought by CBS for $280m (£140m) last year, one of the largest UK web company buyouts of recent years.

“Old Street was a seemingly unlikely place to build a web company when we came here six years ago, but there’s no doubt it’s now becoming a hive of tech activity,” says Martin Stiksel, Last.fm’s co-founder. “The noise, vibrancy, and underground attitude of East London certainly rubs off on you, and inspires fresh perspectives – something I think all these start-ups share. It’s a million miles from sterile, air-conditioned Silicon Valley, literally and metaphorically.”

Right on Silicon Roundabout is Moo.com, which prints business cards based on photos from sites such as Flickr or Facebook, and other real-world products based on virtual content. One dotcom survivor is Moo’s chief technology officer, Stefan Magdalinski, who previously founded UpMyStreet, a local information site, and TheyWorkForYou.com, which helps UK voters find out more about their MPs.

Moo’s founder and chief executive Richard Moross also has a keen eye for a bargain – netting offices for a fraction of local rates because they’re due to be demolished in coming years – and “knows how to throw a party”, according to Matt Biddulph, a neighbour and CTO of Dopplr, a travel site. Indeed, Moo’s summer party last Thursday was abuzz with chatter about the newly anointed Silicon Roundabout, coined last week by Biddulph on micro-blogging service Twitter to describe the “ever-growing community of fun start-ups in London’s Old Street area”.

“For me it’s all about the community here,” Biddulph told the FT. “We moved in because our friends did too.”

He says Old Street appeals because it is away from the throngs of shoppers in Soho, where (for instance) Bebo is based, but near enough to the City and the West End for meetings with financiers or media types – as well as the cheaper areas of east London where shoestring-budgeted entrepreneurs may live. Plenty of hip cafés with free WiFi such as Shoreditch Old Station and Coffee@Whitecross Street are on hand to caffeinate developers.

“Critical mass comes from network of people,” says Biddulph. “There were some really interesting companies here in first dotcom boom, and a lot of the companies here are having their second time around. I’m at my first start-up, so it really matters to me to have people around who know how put a business together – and how to find cheap office space.”

The Dopplr CTO has plotted his fellow Roundabouters on (what else?) Google Maps to lend credence to the idea (see http://bit.ly/siliconroundabout). But Silicon Roundabout’s claim to be the heart of the London tech scene is already being challenged by Huddle, a provider of online collaboration software who is building a similar concentration of talent in Bermondsey Street, South London. Huddle, Moo and Dopplr are all involved in mentoring at Seedcamp, a London event which aims to foster the next generation of European entrepreneurs.

“There are two or three competing camps starting,” says Alastair Mitchell, Huddle co-founder and chief executive. “But competition is good. We’re all trying to grow this community.”

(Thanks to Matt Jones of Dopplr for the photo)