Expected ROI on article marketing... Is this something you can calculate? How many % of all the people will click on my link in my articles?
Yes, I think it is something you can calculate. EzineArticles thell you how many times a URL has been clicked in your article body or resource box. To calculate ROI you will need to have some things set up to track. Investment = (Cost to create and submit articles + Cost of Goods Sold) The % of people that will click on your link in your articles will vary from niche to niche. What is really important is the money you make from those who click on your link. For example, I had one niche that had tons of people clicking through to come to my website but these people didn't buy very much of even click on many Adsense ads. In some other niches I get far fewer clicks but far greater sales. Good luck with your article marketing. It is a very profitable marketing technique.
If you measure ROI purely in terms of clicks then yes, but perhaps of greater value and significance is the link-juice-effect that syndicating articles will have on your search engine rankings. This is far more difficult to quantify, as the value, although very real, is more or less intangible.
I completely agree that there are intangibles that would be much more difficult to measure if measureable at all. One gigantic intangible that comes to mind is credibility/trust. This one by far has been the longest-lasting and most valuable benefit for my personal article marketing efforts.