signs of ppc campaign

First, let me say that, although you specifically mentioned Facebook, my answer is fairly universal for any PPC campaign. The reason is that most have a quality score equivalent which is fair to all and actually makes the ad network the most money this way.

Next is that I'm assuming a few things given the little information. I'm assuming you haven't made changes of any kind to your campaign. You have not added, removed, paused, unpaused keywords or ads nor have you changed your bids. That is not the recommend way to do things but probably what many do.

Having said that, your campaigns don't exist in a vacuum. You have competitors who may make changes often. Competitors also come and go. You really have no idea if today's competitors are the same you had yesterday. They most likely are not.

So you say your cost (you said bid but assume you meant cost) per click is going up. I'll assume no changes on your part. You don't say how much of a change but I'll assume you mean a large percentage increase. To me that's at least 5% and you have to compare apples to apples such as ad position. You also need enough data: you can't compare data five clicks at a time or five clicks versus fifty.

Target audience too small: why would that have an effect?

Nobody is clicking: could very well be. If compared to competitors your click rate is lower, your quality is lower and therefore you are losing ground which increases your costs. That's the point of ad quality: maintain it or increase it otherwise you may find yourself losing ground and paying more.

Increased competition: not necessarily more of it (which could be) but like I said, if you are standing still, existing ones may just pass by you. It's a game where you are trying to pass and stay ahead of others. You won't win if you don't shoot or come to the plate, or any sports metaphor you like.

Yes that the correct sings of PPC networks. I am agree with you.