From where I sit, I think Google needs a couple of things.
The company has been working with Yellow Pages publishers and others to acquire data and information about local and SMEs. A variety of companies — YP publishers, Web hosts, local SEMs and now newspapers — are selling Google traffic. But, ultimately, Google needs to dramatically modify its AdWords sign-up process or develop its own direct channel into the SME market to really gain mass adoption.
Yahoo! is one of the top SME Web hosts and its range of hosting and related services is a direct channel into that market. If Google we're to offer hosting or buy an SME hosting business (Affinity, Interland, Vista, etc.) with existing customers (which is a better idea) it would acquire that channel, a new revenue stream and a prospect base into which to sell AdWords, etc.
Like Yahoo!, Google is already a domain registrar. Buying a hosting business would be more scalable and cost-effective than trying to build a "feet on the street" channel. Google and Yahoo! have publicly said they don't want to do that because of the cost and complexity of managing the channel and related SME relationships.
These comments aren't based on any solid information or rumor, just a suggestion on my part.