yelp.com is crap.
I tried to do a search for "barter" within 5 miles of Sunnyvale,
 got 3 results, none of which had anything to do with a barter
 system except incidental use of the word in a review.
So I tried to file a review of yelp itself:
It required me to create a new account. I did.
It then required me to log in with the e-mail address and password
 I had set up. I did.
It then indirected about ten times and finally put me back to blank
 log-in form again.
I tried resetting my password, and it said it mailed me instructions,
 but 10 minutes later the e-mail hasn't yet arrived.

An hour later I got thanks for opening account and request to verify
 my address, so I did so. I was then able to log in just fine using
 my original password. But I couldn't figure out how to find out the
 address of Yelp so that I could post a review of them. I went to bed
 with this unresolved.

Two hours after that I finally got e-mail to reset my password, which I
didn't see until hours later when I came online again.