Exactly how deep are Microsoft's pockets?

It has confirmed that it is after Yahoo's search engine business and talks are ongoing (after months of wrangling and conflict).

And there are also the rumours that it is in talks to possibly buy the worldwide social networking success that is Facebook, although the site's founder, Mark Zuckerburg, has always said that he wasn't looking to sell.

But now there's yet another rumour.

Reuters is reporting that Microsoft may be after none other than the British listings service Yell (or Yellow Pages as it is also known).

Shares in Yell Group rose 5.4% upon the whispers of a possible bid.

Yell declined to comment.