Google Analytics is an awesome product, and very well thought out too! Now if you want to use (?src=publication), you can go ahead and do it. However, then to track the traffic from that source, you will either have to setup an advanced segment or go to the Content tab and filter by "?src=" as you currently are thinking of doing.
Now look at the alternative, using the a GA URL Builder, you can ensure that your a Custom Campaigns are also easily available in the Traffic Sources -> Sources -> Campaigns tab. No need to create any advanced segments. Another advantage of this is that your site administration can be done by one person and the analysis could be done my different set of people (in which case they do not have to remember the different parameter strings being passed such as "?src=".