From the article at the Columbian.com: seems like they focused on urban areas, cut the proposed tax 50% to 2 cents per $10 (tiny amount), and got some prominent Republicans to support.

Nevertheless, a big win -- two-thirds of voters supporting it! What's next, support for light rail? ;)

From the article:
"The heavy support was a huge turnabout from November, when a sales tax proposal failed after it was rejected by 54 percent of voters countywide....

C-Tran's success will enable the... agency to... keep buses running at 2004 levels for at least six years.

Those promises, in addition to cutting the amount of the sales tax boost, drew unprecedented bipartisan support and strong endorsements from the business community. Two transit advocates with strong Republican Party connections volunteered to direct Save C-Tran, a group urging support for the measure.

To further improve its odds of passing the ballot measure, C-Tran also constricted its service and taxation boundaries to the Vancouver urban area (the city and a portion of unincorporated Clark County outside Vancouver) and the city limits of Camas, Washougal, La Center, Ridgefield, Yacolt and Battle Ground. Last November's measure was submitted to voters countywide, and one assumption was that it was rejected by residents who live outside the service area and therefore had no reason to support bus service."

Would the current high gas prices have anything to do with raising public support for mass transit?

I don't live in Vancouver, but I've heard more than one person be angry over C-Tran cuts. And while I don't know if the gas prices are leading to support for transit, I do know that its been said that more people are riding:

http://www.oregonlive.com/search/index.ssf?/base/metro_south_news/1126781999109490.xml?oregonian?sn&coll=7

Let's hope that C-Tran moves quickly to begin new express service to the Interstate MAX Yellow Line as promised.
Three bus bays have sat unused at the Delta Park/Vanport Station since MAX opened in May, 2004.
Currently most Clark county residents who work on this side of the river do NOT work in Downtown. Frequent all day service to the MAX Yellow Line, comparable, but more frequent please, than the current Parkrose TC service to the Red Line, is long over due.
From the Yellow Line, TriMet provides good connections to Swan Island; other North Portland employment destinations such as Kaiser Interstate, Emanuel Hospital and Lower Albina industrial area are directly on or walking distance from the Yellow Line.
C-Tran's Downtown express buses do nothing for Clark county residents who work in these areas.
Lenny Anderson, Swan Island TMA