I looked at Trover (free) a couple of years ago and found it a useful app for seeing what is around you with photos and comments from real travelers rather than what is contained in a guidebook. It has elements of Yelp, Instagram and other social content aggregators.
When you post your own photo, the app makes it public (so be careful) with all the geo-location data available so you can find a particular location. You can add comments about a photo -- perhaps a nice park, a restaurant, a local festival, whatever you like. You can contact the people who take the photos, and they can contact you. As a result, Trover is kind of a living, evolving guidebook to places filled with images and comments from people who experience them.
You don't have to create a Trover account if you just want to be on the receiving end of the information, but for some people, a big part of the fun is sharing insights.
In my original review, I raised some of the privacy issues I thought the app had. If you take a picture of your house or kids, a dedicated Trover user can get a pretty good idea where that is. My advice is to not get too personal. A zoo, a restaurant, a hiking trail are safe subjects.
Some of the photos people submit don't really merit being in the app. People sitting around drinking or eating with no useful info is not very valuable. Anyone can upload, so all content may not be useful. Offensive content can be flagged by users and removed by Trover, but that won't stop things that are offensive from appearing, even if briefly. According to the developers, it's not a big problem. All content on Trover goes through several layers of curation. According to the Trover team: "We have a team that reviews all new content. Our community also participates in curation, thanking discoveries they like, adding discoveries to lists and (rarely) tagging photos as 'not helpful' if they find something in Trover that doesn't fit with the social norm. Short answer: We never see obscene photos. It's not what Trover is about."
Having said that, users are very happy with the Trover community, and can see the merit of the app for people on vacation, a business trip or even someone who wants to explore unknown areas of their own locality.
The app is solid, and this latest version now has a simpler and faster photo uploader, a redesigned GUI to match iOS 7 and support for portrait photos. In my tests, it found a lot of local places around me, and there were some good comments and reviews of hiking places, restaurants and tourist stops.
Trover is not a universal app, so it's really best used on an iPhone or an iPod touch. It requires iOS 7.