The Internet never forgets. No app is going to change that because Internet is de-centralized and de-centralization makes it impossible to know if the data was really completely removed or not.
Let's face it: the only way to not expose your personal info is to not share it in the first place (forget silly Facebook, G+, Instagrams and all that stuff). If you've already done that, make sure that whatever you are doing that might lead to doxxing is done with your other identity (although this is hardly fool proof since linking identities can happen in many unexpected places). Worst of all is that that kind of infomation, once it slips, is impossible to contain and you have to cut ties and start over.