yelp

Part 1 of Rant - Recommendations from Yelp, foursquare, etc  are useless because there's no way to validate expertise and no identity

social+local+expert data = relevant recommendations aka Yelp, Foursquare, urban spoon, etc are walled garden data silos of doom NOT destiny and they don't really help you find the awesome restaurant  or espresso g*d shot you are looking for despite Fred Wilson's experience (an exception that proves the rule)

Part 2 of Rant - Don't trust your review data not to be compromised and not to be deleted when using a service like Yelp, foursquare, etc

You may be elite-2011-taster-273487 on yelp or urban spoon but or other such location based or recommendation based service, but:

1. you don't own your data e.g. your reviews
2. you can't export your data
3. why should anybody believe that it's you or trust your reviews when it's impossible to figure out who you are e.g. who is JudyS_240394 ?
4. your data will be sold (only Apple seems to have the guts not to sell user data)
5. what happens when the wonderful service goes out of business or "pivots"? 

Part 3 of Rant - Solutions - for now: copy to your site, future: open formats are the only long term way to get out of the silo

It's unfortunate that in 2011 that the best way to build up a consistent reputable, verifiable, track record for reviews or anything else that's structured beyond mere text is still to to have your own site e.g. a blog .

The best pragmatic compromise is to somehow copy the data you post in walled garden data silos of doom back to a site you control on your domain (unfortunately most walled garden sites don't allow you to get your data out without compromise; exceptions that prove the rule: flickr and instagr.am)

Or flip it around: Make your site the master and copy the data out to walled gardens like twitter, yelp, facebook etc is probably a better short term pragmatic solution. Not surprisingly the usual suspects :-) like Dave Winer and Tantek are pioneering this (check out Tantek's falcon system).

And in the long term, a "beyond unstructured blog of text" open API or data format for things like reviews which we have been discussing since 2004 (e.g. microformats) will actually happen. I remain optimistic about that :-) !

I have been blogging for 10 years, started Dec 1999 (dreadnet.editthispage.com which sadly died a few years back due to my own negligence) so some  2010 social media long term predictions and gratuitous advice which again is worth what you paid for it

Social Media 2010 predictions and gratuitous advice:

1. Flickr, Facebook, Twitter, Yelp, Tumblr and other walled gardens are over in the long term; an open solution will replace them in 5 years or less.
2. Don't be afraid to use and experiment with the walled gardens but recognize that your stuff can be deleted at any time and unless you have backed it up to an open format like HTML, it won't last forever (most likely scenarios: service goes out of business or your account is deleted for an arbitrary reason). I wouldn't shed a tear if all my tweets were deleted, YMMV. If you have fun with the walled gardens, get your domain and start a blog, videoblog,podcast, etc., you won't regret having an online presence you own and control
3. If you care about your closed garden stuff, back it up to an open format. If you aren't geeky enough to figure this out, ask a geek, there's lots of them, just don't ask me :-)
4. Have a "hook" and nurture and grow it. Not good enough in 2010 to be a jack of all trades social media whatevah :-) You actually need to *know* something. Most people do (they just don't realize it!) so that's not a problem.
5. Don't know why I have to write this in 2010 department: Don't trust reviews or content on Urban Spoon, Yelp (i like the idea of yelp & other aggregators  but in practise most of the reviews are shall we say not helpful), Gowalla, Facebook etc unless you know the person in real life or have read their stuff over a period of time. Most restaurant reviews like most content on the Internet are wildly biased but that's a good thing because objectivity in food reviews is ridiculous.
6. Get your most valued content out of the walled gardens and your email (email rocks but it's not a place for long term knowledge storage and retrieval) and back it up. The best way to back up is to put the content in an open format like HTML on your own domain and backup all the stuff on your domain. Again, ask a geek. And really most people's stuff that is truly valuable is not a lot, myself included :-)  e.g. I bet my best emails, best photos, videos and blog posts for the last 5 years could fit on 1 DVD!