Several readers suggested topics dealing with inventory. "For a topic, what about ways inventory might be deal with? I was thinking that when it is obvious the bubble has popped there might be a sudden push to expand green space/parks or mass transit. In the Nova/DC area where I live I can think of some good examples like expanding the orange line of the metro west which would require buying up land near I-66 that has houses on it, 'destroying' the inventory."

Adds another, "What are the historical early warning signs that the bubble is collapsing? Is it when inventory bottoms and starts up?"

From the San Francisco Chronicle. "In another sign that the real estate market is cooling, but not collapsing, the inventory of unsold homes in California is roughly double what it was a year ago. Statewide, the inventory of unsold single-family homes in February was 6.7 months, up from 3.2 months in February of last year."

"'We saw a rather dramatic increase at the state level beginning in January of this year and continuing in February,' says Robert Kleinhenz, deputy chief economist with the California Association of Realtors. 'Time on market is a lagging indicator,' says Kleinhenz. 'Unsold inventory is a leading indicator. If inventories are going up now, that means there will be less upward pressure on prices going forward.'"

"Inventories have risen to 4.1 months from 2.3 months last year in San Francisco County, to 3.2 months from 1.7 months in Alameda County, to 5.2 months from 1.3 months in Contra Costa County and to 2 months from 1.5 months in Marin County."

"In Santa Clara County, the median single-family-home price was $765,000 in February and should come in around $760,000 for March. The slight drop, (broker) Richard Calhoun says 'is significant. Normally, prices are going up from February to March. I think in September we're going to be talking about a number like $710,000. I see no upward pressure' on prices."