Well, I've sent you a PM so we can get in touch but never got an answer.
I get an email notification when a new reply is posted in this thread but about PMs the forum doesn't seem to send me any. I'm sorry, now I see I already have three, thanks for mentioning.
why does the dog have to carry the device and not just using e.g. the smartphone?
for two reasons:
1. because I don't want that the system can be used without dogs and the only way it can be guaranteed that they are always present during these activities is by placing something on them that is able to ascertain whether it is being worn by a canine or not. The device monitors its wearer's body movements so one cannot just put it into their pocket or carry it in their bag. If they do so the system will detect that there's no dog so it doesn't let them use it.
2. because this way it can be avoided that personally identifying information get into the system. Your every activity (where you were, whom you met, what you did) appears from your pet's point of view, so you might share these things with others more courageously this way. And although others will have no idea who you are, how you look like who your friends are etc... still, if they like what your dog is doing (e.g. goes to run or hike a lot, where it does it, with what other dogs it does these things together, and what things those do....) they will most probably like you too as you actually do the same:) and they can decide to meet you. So even if they don't know anything personal about you, they know if you're a kind of person they might like.
the financial part (where you explain how your project will make money) is quite a mystery to me.. Could you please elaborate this part
This strange way of advertising can be realized because of the fact that it is an IT system that when you use, you do things in the real world instead of a virtual one and also you are in "a different state of mind":
If you use a social networking site for example or any instance of social media, you have specific things to do (you might be talking to someone, looking for somebody, seeking for specific information about an event or band, watching a video or idk) ...and ads are coming to you. whether you want them or not, whether they are relevant or not. And they even hinder you in doing things (take up much space, cannot skip them, etc) and this way they may very well be annoying. you don't want them.
The difference in my solution: Think of a billboard in the street. It is a thousand times bigger than an ad on your smartphone's screen, still it doesn't annoy you because it is not getting in your way. So in my system the advertisers can place many "virtual billboards" to anywhere in the real world and if you pass by one, your can read them on your smartphone. - and only if you want! you can turn this thing off completely if you want, but here is the difference: Why wouldn't you do that?
because you are doing an activity during which you are open for any kind of information. You walk your dog. If you'd be going to work let's say (or drive your car somewhere, going to school or to a meeting, so you have some specific to do, some aim in your activity) you don't want to feel your phone vibrating in your pocket telling you there's an ad are you interested? But dog walking is something else. You're not going anywhere, you don't have to be there in time, you can take your time, it can even get boring alone in the evening in an empty city. So you seek for input:) you seek for information, and if you discover an ad, you might even be happy that someone's talking to you 
At the beginning it is a GPS-based proximity marketing. An advertiser can "place an ad onto a hofer or spar" so if you pass by the store tells you to come back tomorrow because the beer will be cheaper. In the future, as IoT becomes more prevalent, maybe an ubahn will find you with offers of the wiener linien, or even a backpack from someone's back you pass by advertising the new collection of the h&m or idk... (are they selling backpacks?:))
So.. I hope I could make it a little clearer:)
