The chart above plots the inflation-adjusted dollar value of all Department of Justice asset forfeitures from 1989-2013. It includes both civil asset forfeitures, like the ones discussed in the Post's investigative series, and criminal asset forfeitures, which occur when police seize property from defendants formally accused of a crime.
You can see that the amount seized has risen sharply in the latter half of the last decade; 2012 represented a high-water mark, when approximately $4.6 billion of cash and goods were seized. While the Department of Justice doesn't provide a comparable breakdown of civil versus criminal seizures pre-2008, data since then show that civil asset forfeitures have more than doubled, from $508 million in 2008 to $1.1 billion in 2013.
While many factors likely contribute to the increase, one major component is the rise in post-2001 "stop and seize" traffic stops documented in the Post article.
The Post piece notes that under civil asset forfeiture laws, the burden of proof is on the owner of the assets to show that they are not related to a crime by a legal standard known as preponderance of the evidence. In essence, you're considered guilty until proven innocent.
Previous attempts at reform have largely been stymied due to intense lobbying from law enforcement groups, for whom asset forfeiture can be a significant source of revenue. From a political standpoint there's something for everyone to hate about the practice. Liberals note that it disproportionately affects poor and minority citizens, while conservatives are inclined to see it as a gross overreach of state power.
For more on the practice, read this 2010 Institute of Justice report.