There are three rentals in my city that have been on the market for 100+ days. One has been on for 119 days! That is almost four months without income for the owner. Just one year ago you could rent a place in two weeks flat. Nothing, and I mean nothing sat for more than 30 days. There are a bunch of houses in the 90/70ish day range on the market too. But when houses get into the 100 day range something is seriously sideways.
Also, there is starting to be a lot of news articles like this: Twenty one percent of SF rentals cut prices. So far it looks like the overpriced rentals.... but we will see how things go. Even during the Great Recession rents only fluctuated about 5%. But as always - we are uncharted territory.
Now I understand why I'm starting to see a bunch of articles about what a sucker you are to own a house again. The funny thing about those articles is they name all the reasons not to buy a house, but they never list what the typical rental increase is every year.