What information does Google Adsense collect when you click?

Apparently I'm wasn't the only one interested in what kind of information Google collects when a person clicks on an Adsense ad. There's a thread at Webmaster World from 2007 that talks about some of the variables passed to Google and what they possibly mean.

The Webmaster World thread leaves a lot to wonder, and others have dissected Adsense as well.

It should be interesting to note that among the many bits of information that are passed to Google as a result of an adsense click are the following variables:

• Color of the Headline, ad text, background, border, and url of the clicked ad.
• Obvious things like screen resolution and color depth.
• Whether or not Java and/or Flash is enabled.

That's all pretty standard visitor tracking stuff. But what really stands out amongst the many Adsense variables passed to Google's servers are the two following parameters which should be self explainable:

• cust_gender
• cust_age

I bet you didn't think Google Adsense was so personal.

What other parameters are passed to Google when a person clicks an Adsense ad?

I thought you'd never ask!

Using a script that processed close to 200,000 Adsense ads, I've collected 107 different parameters that get passed to Google Adsense. Here's the unique variables that I found:

dt, lmt, prev_fmts, format, output, channel, url, color_bg, color_text, color_link, color_url, color_border, ad_type, ref, cc, u_h, u_w, u_ah, u_aw, u_cd, u_tz, u_his, u_java, u_nplug, u_nmime, kw_type, rt, hl, kw0, kw1, kw2, kw3, okw, loc, alt_color, alternate_ad_url, kw4, kw, cust_id, adsafe, pv_ch, ai, num, adurl, client, u_, oe, color_line, bid, hints, nm, nb, jca, flash, correlator, ui, region, slot, random, contents, skip, adtest, host, clkt, nh, src, ad, SiteTarget, ga_vid, ga_sid, ga_hid, ga_fc, prev, prev_slotnames, slotname, google_ad_channel, ca, ed, cust_age, gl, cust_gender, cust_l, cust_lh, frm, num_ads, image_size, targeting, ff, feedback_link, s, prev_fmt, ga, ggladgrp, gglcreat, a, ea, eid, w, h, xpc, p, biw, bih, adx, ady, dtd, dblk, gen_204

I don't know what every one of these GET variables stand for and I'd even guess that there's many more.

And if you've read this far, you probably have some reason you're interested in reading about Google's behind the scenes tracking information.

If you have questions or would like to exchange notes, use the comment box on this page.