In my winding discovery tour at the Web 2.0 Expo in San Francisco this week I’m sniffing out two of my favorite themes these days. I’m looking for how SOA and Web 2.0 relate, and I’m listening for the rumblings of how innovative advertising will augment the subscription model for SaaS and mashed-up web services in business use.

So far I’ve been able to find a SOA angle for many of the approaches on display and solutions that are top of mind in conversations here. That is to say, many Web 2.0 features and functions will have a bearing on the enterprise, even if they find traction first through use-cases in the consumer-facing web.

The social media mechanisms can provide value to how IT provides productivity to workers, and allows workers a freer hand in making their jobs faster and easier. As for the contextual or semantically endowed ads, I’m getting less resistance to the notion than in the past. It’s no longer taboo to think about ads in your spreadsheet or ERP interface. This tells me that attitudes toward useful ads — perhaps sanctioned in some way for business use only — in the context of work, as a quid pro quo for low-cost hosting and application services availability, is an inevitable part of out future.

Indeed, I asked about business apps as platforms for ads in a press conference with the expo’s organizers. They reacted lukewarm to the idea, but not with antagonism. One person thought that Microsoft was in the best position to begin to explore these models. We should also expect more from Google on this level as well.

A best example of the intersection between SOA and Web 2.0 here at the expo came in a discussion with JackBe, which is exploring more commonality between SOA activities and Web 2.0-type RIAs. What really grabbed me in my chat with JackBe CTO John Crupi was the recognition that governance needs to permeate beyond the server to the client — to provide a two-way street for services use and access. And this malleable governance needs to be of a federated variety such that the top-down inputs and attention learning from the users can play a role within the larger guidelines set from the bottom up by IT.

I’m not saying we see this yet in the field much, but the best of Web 2.0 social wisdom benefits coupled with the security and use-governance policies enforced by IT necessities makes for a powerful combo. It’s about a hybrid approach to how to manage SOA and business processes that protects IT while tapping the experience and innovation of end users. The wisdom of the workers? Incidentally, we discuss how the way governments operate offer some concepts about how IT and services might be governed in a recent BriefingsDirect SOA Insights Edition podcast and transcript.