In response to aggressive competition from rivals like Yelp, Citysearch — the popular local events and review site owned by IAC (InterActiveCorp) — has gotten a full makeover. There’s a more streamlined and Ajaxified UI and some other important features have been tweaked as well. The company said this is about a year and a half in the making. At the start, the new features will be available on a separate beta site.

The beta site is expanding to become more “local” that creates listings for more than 75,000 different cities, adds social features through Facebook Connect, and launches an improved mobile compatible site which supports a number of different mobile browsers and handsets including Apple’s iPhone.

The new site now allows you to login using your Facebook credentials to write comments, reviews, and see what other Facebook friends are doing there. Elliot Schrage, Facebook’s VP of Communications and Public Policy, said in the joint release:

At Facebook, we’ve found that remarkable things happen when you get trust, user control and identity right–people share more information, and become more open and connected, Citysearch’s innovative new site shows how Facebook Connect can help information flow faster through a site while creating a filter for users to engage with localized content through the lens of their friends, family and colleagues.

This is a good move of Citisearch while fast-growing start-up Yelp has started to gain some market share in the “user-generated reviews” section though, according to Compete, it is still smaller.