Yelp is now more visible on the iPhone, thanks to a deeper integration with Siri. Previously, when you searched for local business categories through Siri (e.g., “show me restaurants”), you received a list ordered in part by proximity and partly by ratings/reviews.
If you selected any of those listings you were taken to (Google) maps on the iPhone. You could then either call or get directions. However there was no obvious way to get any of the deeper content Yelp had to offer for the particular business.
As of iOS 5.1, you can now tap on the star ratings and go directly to the profile page in the Yelp app, or a mobile web page if the app isn’t installed. In the past you were able to scroll to the bottom of all the (Yelp) results provided by Siri and then be taken into the listings on Yelp, but that was largely buried.
The new implementation is still a bit awkward. If you tap the listing on the left side of page you go to the map. If you tap the star ratings you go into Yelp. People will have to discover this.
Overall however it makes local search via Siri more useful. Previously it was nearly worthless. It also illustrates how Siri will probably start tapping more deeply into a broader selection of apps over time, which was the original aim of Siri pre-Apple.