The company I'm building right now has something similar to this as a major component of the service (feedback via text [SMS->email for the moment, but I'm also going to have it be visible in a web dashboard] ] is one of two methods I'm going to launch with.) I'm billing it as a "universal customer testimonial" service with a some added benefits. One of those benefits works like this: a business receives a message sent in via text. In order for the message to be posted publicly, the business has to approve it, but even if the business chooses not to post a message, they can read it and act on it (I include a message with each approval request that says 'If you do not wish to approve this testimonial, you may ignore this message. However, we do recommend taking even negative feedback into consideration in order to improve the product or service you provide.') So they get customer feedback, and can then choose to turn that into a public testimonial, or they can not post it publicly but still act on it.
Another benefit is a 'remind to review elsewhere' message. If the business approves the message, we send a reminder to review the business or product on a service of the business' choice (like Yelp, Amazon, etc.)
I'm hoping that the extremely low barrier to use (sending a text), will mean that these businesses get more feedback (since there are plenty of people who don't want to post on services they have to register for; don't feel like downloading an app; who wouldn't mind giving some feedback, but don't want to feel the pressure of 'crafting' a reply the way you often do on some services; who, even if they are registered, may just put it off forever because it seems like too much work, etc.) and so will have more information with which to improve their businesses. The idea is based on the 'praise publicly, criticize privately' maxim.
I worked on creating a similar service for a few months in regards to helping businesses (SaaS companies specifically) capture testimonials. I ultimately decided not to pursue the idea after having conversations with potential customers. SMS was not going to be a feature in the initial version and we may have been targeting different niches but I would definitely recommend getting it in front of your target audience as soon as possible or just talk to them about it.
I found that most SaaS companies wanted a few really well written and well placed testimonials rather than a constant stream of subpar testimonials and didn't really need a system for that.
It sounds like you may be going more towards local small businesses though and maybe they have a need for it. Happy to discuss any questions further with you if you'd like.
My starting market is definitely local businesses, though I do think there might be hope for online companies too (one idea for subsequent versions would be to have the ability to turn Twitter/FB/forum posts and linkable web comments into testimonials with just a couple of steps, rather than going through the whole copy post->go to your CMS->reformat it stuff. There will also be an embeddable testimonial board.)
I'm pretty far along with the initial version to demo it to them, so I should have it front of them fairly soon. Dealing with sub-par testimonials is something I thought about early - that's part of the reason everything requires approval by default. I'm hoping these businesses will post the great ones, appreciate, but maybe not post the so-so ones, and take seriously and act on the negative ones.
Ultimately, I'd like it to cohere from three things: a central place to aggregate reviews/testimonials from many sources, a customer feedback system, and a "reminder to review elsewhere" (to nudge the marginal reviewer to actually leave that Yelp review) service rather than just a feedback system like TalkBin or Talk To the Manager.
Another benefit is a 'remind to review elsewhere' message. If the business approves the message, we send a reminder to review the business or product on a service of the business' choice (like Yelp, Amazon, etc.)
I'm hoping that the extremely low barrier to use (sending a text), will mean that these businesses get more feedback (since there are plenty of people who don't want to post on services they have to register for; don't feel like downloading an app; who wouldn't mind giving some feedback, but don't want to feel the pressure of 'crafting' a reply the way you often do on some services; who, even if they are registered, may just put it off forever because it seems like too much work, etc.) and so will have more information with which to improve their businesses. The idea is based on the 'praise publicly, criticize privately' maxim.