Your competition is direct messages between friends and coworker mailing lists. These seem inefficient, but they have the benefit of reinforcing a relationship. If I want to find a service provider, is it easier to message all my friends and ask them to send me the info, or to message all my friends and ask them to sign up for this app, then enter the info in the app? Obviously the former is easier. So you have to somehow convince folks that proactively putting this info in one time in your app is either going to a) save them effort later, or b) make their friends more grateful to them than they otherwise would be if they just waited for a friend to ask. Personally I think b is more likely to happen, e.g. I have a great experience with a plumber in January and write it in this app (like a little journal), then my friend Alice needs a plumber in July. She doesn't think to ask me, but happens to check the app, and sees that I recommended a great one and they do a great job for her. Even though she didn't message me, I want to still feel like I did Alice a favor, but without her even having to ask. And maybe that little act of entering in the plumber will help 5 people I know over the next few years. I also want Alice to see my entering in these details as an investment into our relationship because I care about helping Alice out. Maybe I want to see "Alice saw your recommendation for plumber X" or even "Alice called plumber X" and we can talk about it next time we see each other and compare notes.

Another thing I'd wonder as a consumer running across this (rather than as a personal friend of yours) is what's the revenue model going to be. If it's not serving me ads, is it collecting my contact list and selling that instead?