Personally, I think that coming up with a solution to the problem of “keyword not defined” entries from Google is the biggest challenge for Piwik.
The information is available, because it is displayed on a public website that can be cross-referenced. It is simply that the header information is no longer being sent computer to dcomputer for tracking purposes.
What innovative ways are there to combat this and get keyword information?
After all, there are clues available. We know:
1/ The page being accessed - This dramatically cuts down on the potential searches producing the referral.
2/ Referer information from other websites - This again produces a list of potential searches it might be. Information from Bing and Yahoo should narrow the field (while they still send it)
3/ The position of the query on the Google search results page - So, even if we don’t know the phrase, we know the position on the page, as well as the geographical position of the person who made the search, so you can further narrow down the possibilities. if a person from that IP in Alabama did that search, then we know we are looking for the third result on page one etc.
Might it not be possible to have an auto-query function if a “keyword not defined” entry is returned to make use of the above pieces of data to go back and query google and come up with a “best guess” as to the phrase being used?
That might not be perfect, but it would certainly be far more useful then 90% of all the queries having “keyword not defined” next to them, which is a total waste of time.
It would also dramatically set Piwik apart from Google Analytics, and in turn, have the effect of putting pressure on Google to start providing the information again.
Google is behaving in a monopolistic way because there are no alternatives and they are strong-arming webmasters towards paid advertising (who DO get access to this data - so much for “privacy concerns”!)
So, in my book,coming up with alternatives to “keyword not defined” is absolutely the most pressing problem that Piwik needs to fix.