In another indication of growing interest among VCs in Web 2.0 outfits,


has raised US$15 million in a round of financing led by existing backer Index Ventures.

The Paris and London-based start-up, which claims to have recruited five million users of its customisable Ajax home page, plans to use the funding to help it take on rivals such as Microsoft’s and Pageflakes.

According to Siliconbeat, the move follows another round of financing in March, which involved, among others, Netscape co-founder Marc Andreessen and Kelkoo founder Pierre Chappaz.

Index Ventures and Accel contributed to the latest round of investment, which along with Bebo‘s recent cash injection from Benchmark Capital amounts to one of the largest such deals of the year so far.

The firm, formed by journalist Tariq Krim last year, claims to be adding users at a rate of one million per month, and the new money will undoubtedly help it to expand its user base further.

With uptake of Ajax-based services increasing, it will be intriguing to watch how Netvibes and its investors plan to turn that popularity into hard cash. Because a smattering of Ajax does not – unfortunately – make a solid business model.

That said, the Netvibes site is highly cool. It works well, and it is intuitive. But does it really have five million users, or has it simply ‘had’ five million users? We ask because new visitors can customise the Netvibes page without creating a user account, and a cookie means that you’ll see any personalised changes the next time you return, which is a nice touch (until you delete your cookies, of course). Yet Netvibes probably needs to do more to capture email addresses and to build up user profiles, to be able to claim five million returning users.

We refer to sites like Netvibes as ‘Ajax homepages’ (note to the geek mafia: that’s different to ‘Ajax on homepages’). Others call them ‘personalised start pages’. Or ‘customisable homepages’. Are they sustainable? Do they need this amount of funding, just four months after taking a seed round? We’ve delved into some of these issues previously, in an article called ‘Are all Ajax homepages doomed?’.

The Netvibes business model is largely undisclosed, although clearly investors are satisfied that the company is more than cool technology. Third party widgets are thought to be the way forward, though we can immediately see affiliate action with those Kelkoo links (do users get a portion of affiliate revenues?), and there are certainly some white label opportunities to explore. Moreover, it could become a social shopping play.

Netvibes rocks, as a web app. We love it. We’d like to know a bit more about the business model, the sustainability of that model, and the split between the first time user who happens to customise before disappearing into the ether  vs returning users who consistently use Netvibes as their ‘personalised start page’.

We’d also love to know how much equity has been forsaken for this investment, and what the money will be used for.

At any rate, well done Team Netvibes. It is great to see European startups bagging investment from respected investors.