Piwik originates from France and almost all the attention so far has been from outside USA. It seems to be catching on in Japan and China, as well as in Europe. The team responsible for Piwik seems to be made up of interns from big companies such as Amazon, Intel and even Google.

You need PHP and MySQL to use Piwik, which is no problem for techies but any widespread adoption will need a hosted version. Some entrepreneur is likely to offer that. Plug-ins to WordPress and other blogging platforms will also be needed, but cannot be that hard.

Open source products usually get traction, even when they are raw, when the alternative is too expensive or restrictive. Google Analytics is free, so it is hard to see rapid adoption by bloggers and small media companies. It is possible that Piwik will get better traction in companies that already use one of the expensive web analytics services from companies such as Coremetrics, Omniture and Visual Sciences/Websidestory.

Larger companies may have some pause for concern before switching to Google Analytics, because of the service's Terms of Service. An analyst in the IT department is likely to point out two clauses (yes big companies DO read this stuff):

"2. FEES AND SERVICES . Subject to Section 15 herein, the Service is provided without charge to You for up to 5 million pageviews per month per account, and if You have an active Adwords campaign in good standing, the Service is provided without charge to You without a pageview limitation.

Google may change its fees and payment policies for the Service from time to time including but not limited to the addition of costs for geographic data, the importing of cost data from search engines, or other fees charged to Google or its wholly-owned subsidiaries by 3rd party vendors for the inclusion of data in the Service reports."

So, don't go above 5 million page views without paying something to Google via AdWords. That may make one a bit uneasy, but it is the "Google may change its fees and payment policies" that will have both IT and Legal aiming to nix the deal.

Then a bit later on you get:

"6. INFORMATION RIGHTS AND PUBLICITY . Google and its wholly owned subsidiaries may retain and use, subject to the terms of its Privacy Policy (located at http://www.google.com/privacy.html , or such other URL as Google may provide from time to time), information collected in Your use of the Service. Google will not share information associated with You or your Site with any third parties unless Google (i) has Your consent; (ii) concludes that it is required by law or has a good faith belief that access, preservation or disclosure of such information is reasonably necessary to protect the rights, property or safety of Google, its users or the public; or (iii) provides such information in certain limited circumstances to third parties to carry out tasks on Google's behalf (e.g., billing or data storage) with strict restrictions that prevent the data from being used or shared except as directed by Google . When this is done, it is subject to agreements that oblige those parties to process such information only on Google's instructions and in compliance with this Agreement and appropriate confidentiality and security measures."

In short, they have the right to use your data. We have lived for a long time in a world where Microsoft and others charged for the software and kept it under a tight IP control, but did not try to take any use of the data. Google reversed that. Google is happy to let you use anything for free, as long as they get to use your data. That is OK for most individuals and small businesses, but totally unacceptable for large companies.

Piwik is working hard to be developer-friendly, not just relying on open source. They claim 4 big advantages:

1. Open API
2. Plug in architecture
3. Data abstraction layer
4. Customizable dashboard

But the nub of the issue for most big companies will be the data ownership issue. That is why Piwik is really a Google Analytics alternative, even if they will see few firms switching from GA initially. IT groups, under pressure to cut costs, will look at Google Analytics as an alternative to their current analytics software and reject the option based on TOS restrictions. Then some bright spark will Google the term "open source alternative google analytics" and see Piwik on top of the organic listings.