Never used Yelp, don't know much about it.
Totally unethical company when they started out. They would seed the site with bad reviews and then "blackmail" company owners to pay for a premium account which would allow them to remove the negative reviews.
After initially claiming this was not true, they back-paddled and said they did in fact hire "reviewers" to seed the sites, and that some rogue sales people would pitch companies on the concept of paying and removing negatives -- but claimed this was not company policy.
Like Facebook, I am wary of any company that starts off on an unethical bad foot. If the original management is still in place, so are their ethics.
I have not been on Yelp in several years. I consider their reviews worthless, (a combination of constant complainers, paid promoters and SEO types, and friends and employees of company's who artificially pump in good reviews).
It looks like were back in pre-bubble burst IPO days for web based tech stocks.
...ok, while I was writing this I decided to look the site over -- give them a fair chance.
"Two Thumbs Down" is my rating. The reviews are a mix of "negative" real people's complaints, and obvious paid and friends of business' reviewers, (How can I tell you ask?)... The negatives will give 1 to 2 stars, and usually be people with 5, 10 or more reviews under their belt. The positives will give 5 stars, and either have 1-2 reviews they've posted (friends and employees asked to post a positive review), or 200-300 reviews -- these are the paid reviewers, (or "online reputation management professionals" as they call themselves) -- the paid reviewers also use very SEO-centric wording, type in full sentences, or mention the full name of a sales person in the case of insurance, car, and other commissioned sales where the business has many.
I'd like to hear what Yelp plans to invest the investors money into -- as I see it they have not innovated in years -- just added more paid advertising.
My IPO thoughts are "jump in and out quick if you're going to play"... long term doesn't look good to me.