Having spent the first 10 years of my career working in Direct Marketing, I am well versed in the idea of marketing as a campaign. 

The process is:

1. Client briefs agency “we need to sell 2,000 mortgages this quarter”
2. Creative staff work on the design and data planners work back from that 2,000 figure (with expected response rates and conversion rates) to identify how many prospects need to be contacted/exposed to the ad.  If they are more sophisticated, they will have data (triggers, profiles and predictive models) to help them identify the best prospects.
3. Campaign is launched and after a period of time, the number of new mortgages is calculated
4. The agency can calculate the ROI from the campaign and then rest easy with a G&T at the nearest swanky bar

The fundamental nature of online communities and their benefits don't change just because the economy has taken a change for the worse.  Even a whole lot worse... What does change of course, is the quantum of benefits (ie. less consumers reaching for their credit cards...) and the scrutiny that all marketing activities will receive from corporate decision-makers. This brings into sharp relief the inevitable comparisons across the marketing mix. This is a good thing...  if you are prepared!