It seems Microsoft's interest in owning Yahoo – or at least part of it – hasn't waned. According to multiple reports, the company has signed a confidentiality agreement with Yahoo, allowing it to take a closer look at the struggling company's business as they explore various options for striking a deal.

Microsoft joins several private equity firms that are also poring over Yahoo's books and operations, including private-equity firms TPG Capital and Silver Lake.

Contrasting with their very public failed takeover attempt in 2008, this time around Microsoft is only looking to help finance a bid as part of a consortium and not buy Yahoo outright, sources say, in a move to safeguard its ongoing web-search partnership with Yahoo.

If you recall, Microsoft forged a 10-year agreement to provide search technology to Yahoo under Carol Bartz' tenure. The deal has played an important part in Bing's growth. Conceivably, should a rival company acquire Yahoo it could seek to end the deal or demand terms that are less favorable for Microsoft. Controlling a minority stake in Yahoo might be enough for Microsoft to maintain the current arrangement without having to pay through the nose for an acquisition and shouldering the operational responsibility for Yahoo.

Such a move is markedly different from what Microsoft tried in 2008. Back then, the company was willing to spend close to $46 billion to buoy its search position and compete with Google. Yahoo, led by its co-founder Jerry Yang, rebuffed the offer and after a months-long battle Microsoft walked away.

Without knowing it Microsoft actually dodged a bullet when it failed to acquire Yahoo – at a 62% premium, mind you. Not only did the economy and stock market collapsed, but Yahoo has floundered ever since and today the company is valued well under half of what Microsoft was willing to pay in 2008.