In a wide-ranging interview this afternoon at ILM:09, ILM Program Director and conference chair Matt Booth tried several times to pin the Yelp COO, Geoff Donaker to the mat. But the unflappable and diplomatic Donaker just wasn’t going to go there.

Donaker spoke with surprising humility about Yelp’s phenomenal growth, from around 14-15 million uniques in late 2008 to some 26 million uniques last month. He emphasized Yelp’s focus on “Quality over quantity” when it comes to building their inventory of reviews. He highlighted their “one city at a time” growth strategy, which seems almost counter-intuitive in our era of buzz-driven hockey stick growth expectations.

In fact, Donaker maintained that it is exactly this ‘go slow’ approach that is responsible for Yelp’s success and staying power in the review/social network space.

For the data hounds out there, Donaker offered up some juicy stats, e.g:

-Restaurant reviews comprise 29% of Yelp’s inventory of reviews

-Reviews of various retail establishments comprise about another 22%

-Reviews of nightlife venues are (surprisingly) small

-Many Yelp reviewers post reviews in multiple categories – effectively using Yelp as their “lifestyle blog”

-Yep now has “community managers” in about 33 metro areas in the US and selected international markets

-Yelp has about 300 employees total, of which about 200 are client-facing

-They have over 100 partners who republish Yelp’s content (with permission)

And finally, back to Donaker’s diplomatic style:

Booth asked several questions about competitors, such as Google with its Favorite Place program (scannable window stickers for businesses that when scanned from an appropriate mobile device, take the user to the Google location with business profile and other information on that business). Booth also asked about AOL’s announced intention operate local sites in 100 US communities, in direct competition with Yelp.

To these questions, Donaker’s response was, in so many words “this continent is big enough for all of us”.