Sorry that Rhinebeck appears to be sold out. Right now, we don't offer a way of being alerted when inventory in a given area opens up. However, in the meantime, you might consider a nearby city or ZIP code.
One thing that should come in handy is that when you're setting up your ad, we recommend nearby locations if the location you've chosen is sold out. So, for example, in Rhinebeck, nearby locations that appear to have available inventory are Connelly, Port Ewen, and 12572. Please note that whenever a city is sold out, it's worth checking the ZIP code and vice versa. This is because ads targeted toward the city appear on our search page, but ads targeted to ZIP codes are shown on listing pages.
Hope this helps!
Trulia Local Ads Update:
If your City or Zip code is sold out, you can now sign up to be on the waiting list. Just enter the location you would like within the Local Ads section of your My Trulia account and click the "Alert me when it becomes available" link.