Mobile apps is really a good way to earn money, cause mobile market has a lot of clients, that ready to spend their money on your products. If you're app developer and dont have your own signature, than i can recommend you this
outlook signature generator. If you doubting that you need that here is few benefits of having signature: gives quick access to your contact details, provides social proof in your email and most importantly it promotes your services, products or offers and drives traffic to your site or app. Create your own signature for yourself, you wont regret it.