My main project is just what you are asking for, we are still in an early stage but we already are solving some of the problems that you are talking about.
First let me start talking about our competitors, because it’s not my intention to promote my solution, but help in your needs. You have Mixpanel, KISSMetrics, RJMetrics (if your budget is high), you have Funnel and you have Interstate among other. If you are a GA ninja you could also achieve part of what you need. All those tools could help you.
We had the same problem and we didn’t find any solution, so we decided to build an internal project, like many others do. But then we decide to focus on it and make it our main project because it was really interesting.
The problem with many of those tools is that they don’t have in consideration the spending of your marketing efforts. Without it, you can’t have your CAC or CPA. In Tractionboard we are solving this through integrations with the major ads networks (Adwords, Twitter Ads, Facebook Ads, Adroll… etc). Our goal has been to make the implementation as easy as possible. Also to be able to track everything, you need to tag your campaigns properly, this is the most important aspect to start measuring your marketing efforts. Without tags (utm_campaign, utm_source… etc), attribute conversions to any campaigns is really difficult. That’s the problem that you have with what @aeden asked “a prospect sees a tweet by us”, and @Clay_Nichols addressed. If the prospect doesn’t click on the link (and it is well tagged), attribute that a future visit to that actions is not an easy task (but not impossible, however it wouldn’t be 100% accurate because you would be attributing by probability and based on times… long history).
About the tagging aspect, our integrations take care of it, because we have noticed that many marketers don’t do it properly.
Once we have the campaigns tagged and we are able to collect the daily spending, through a tracker in your website (similar to the one from GA), we track your visits, attributing them to the proper campaign. We use different techniques to track the same visitor through different sessions (cookies, fingerprints… etc). Once the visitor convert to user, then our life is easier, because we start working with the id of the user, so it doesn’t matter that the user change the browser, clean cookies, or even change the device, as soon as he is identified, all its tracks are assigned to that user id journey (we do it retrospectively, so we don’t miss the iterations before the identification).
At this point we have the spending + the different iterations of the user in your website. What you want to measure is up to you, it could be conversion to user, conversion to customer, trial, “feature X enabled”… whatever.
Currently, how we show the information that we collect is individually per source/campaign. You can choose the conversion goal, the date range of the conversion and the attribution model (first touch, lineal, last touch U-shape… and working on a data driven one), and other options. The view is gonna tell you if a certain campaign is good as an opener, an assistant or a closer. And you are gonna have the spending of the campaigns attributed to the conversions.
We also are storing much data to offer in future other information like for example the revenue, the journey of your user… etc. But right now we are focusing in the CPA and the multitouch attribution.
I’ll be happy to answer any question about the topic.