It would be interesting to be able to assign a visitor to a campaign, as well as having it assigned to a search or website referer.
Note: users who wish to achieve this can probably achieve a very similar functionnality by using Custom Variables (name="campaign", value="Amazing campaign")
We have seen this feature request a few times in the forums. I think it makes sense and would be useful to have.
Implementation: we would need a different field for campaign name/keyword, currently the referer fields are used.
Current feature is perfect as it is: we credit only one referrer. If we start crediting potentially 1 campaign AND 1 website for each conversion, there is the risk to over-report revenue.
Using Custom Variable is a good option in this case and we should simply document this in a new FAQ.