Monitoring Internet traffic to your blog or social network

If your network is hosted externally (on Ning.com in particular), how do you monitor the traffic? Below is what I do, in particular to assess the quality of the PPC traffic from Yahoo:

• All paid clicks go through a redirect; the redirect server is hosted internally so I can track time stamp, browser, keyword, campaign ID, and in particular the referral
• All pages on the external network have a beacon (clear gif) hosted on the internal server (same as the server used for the ridirect)
• The beacon provides information about visit paths, while the redirect provides information about the original referral domain
• I reconciliate the beacon with the redirect data, to assign conversions (or lack of) to specific keywords and referral domains (to detect and block domains with no conversion)

Are you using a different methodology? Maybe something simpler?