Everyone's favourite Microsoft fella Steve Ballmer has been at it again, this time telling a Mumbai conference that Microsoft "didn't make a mistake" over Facebook. Last month Microsoft took a $240 million stake in the social networking giant.

He also hinted to Reuters that Microsoft may yet be interested in doing a deal to suck up Yahoo. The web giant has been in the doldrums recently, yet it still has the kind of reach Microsoft would find useful as it battles its new arch-enemy, Google.

Facebook worth every penny

As for Facebook, Ballmer says that despite the cash injection being worth 1.6 per cent, "the valuation of Facebook is still to be determined". His comments were designed to deflect attention away from analyst predictions that Microsoft had overspent on the stake.

"Today, it's very, very popular. So for a company like ours that wants to be a pre-eminent presence in this space, it's very important for us," Ballmer continued, somewhat predictably. Microsoft won't admit it publicly, but it has been held a little to ransom by Facebook, which originally said it didn't need to link up with any other firms.

Woo-hoo for Yahoo?

"Will Facebook be worth $5 billion, $15 billion or $50 billion some years down the line?" asked Ballmer. "[It] is really up to their team and how they take it forward."

Ballmer said last month that the company wasn't interested in doing more deals such as the aQuantive acquisition. That deal cost the company over $6 billion (£3 billion), but gave it a foothold in the online advertising space. Instead, Ballmer said it was interested in doing smaller deals.

When Ballmer was asked specifically about Microsoft's interest in Yahoo, he replied "my answer is a considered 'no comment'. We want to succeed in the online advertising space. What happens with Yahoo, we'll all have to wait and see."