Google Analytics on the Daron's Guitar Chronicles web serial

Here’s a post for those of you interested in how weblit and serialized fiction work on the Internet. So, now that August is over, I’ve been looking at the Google Analytics stats on the Daron’s Guitar Chronicles website, because it’s interesting to me to speculate about visitors and patterns and what brings people to the story.
There’s a definite difference between the stats while I was posting fresh content 2-3 times a week, and the current hiatus. Here’s what I’m seeing:
History
The site was launched in November 2010. Posting of the story was never below 2 posts a week, and peaked at 4 per week when bonuses were in full swing. About half the time there were three posts a week.
The average number of visitors went fairly steadily up from the start right through May 2011, peaking around 250 per week. There were temporary bumps in traffic some months where I ran Project Wonderful ads, which would bring several visitors per day.
Before Hiatus vs. Hiatus
The three months before going on hiatus were of course the best traffic ever, since things just kept climbing. There appears to always be a bit of a lull on all my websites in July. (My guess is that the number of people who are traveling or on vacation and not surfing the net creates that effect. Though why it rebounds in August, I’m not sure.)
I expected that traffic would fall off to nearly nothing while I was not posting new content, since previous readers of the site would probably not be visiting until new content appeared. However I’ve been pleasantly surprised that traffic has only dipped a little. Compare last year’s traffic to this year’s:
In visitors per month:

The three numbers in particular I want to compare are Mar-Apr-May from this year and June-Jul-Aug of this year. The total number of visitors does go down, but the numbers stay quite respectable.
So who are these folks and why are they visiting the site.
Some come from ads running via Project Wonderful’s network, on webcomics and blogs all over. But some significant number of them are coming from Amazon, where book 1 of the ebook versions of DGC is free to download, and books 2 and 3 are $2.99.
Check out these comparisons:

The folks visiting the site now are more likely to be first time visitors, they stay on the site (and don’t bounce immediately away), and when they do, they stay for twice as long as previous visitors.
That makes sense since if people are new to the site they might sit and read a large chunk at one time, whereas when I was posting regularly, the regular readers could just catch up on a chapter or two per visit.
The most important thing about this is simply that the free ebook, which was downloaded about 3000 times the first month it was offered and which is now going at a rate of about 500 a month, is clearly bringing interested folks to the site to read.
The most intriguing thing is that far more of the commenters in the population of new folks are male than we ever had before. Several of the recent commenters are either male or using male pseudonyms (which is the same diff to me).
For those who are curious about how a free ebook spurs SALES on the Kindle store, well, right now volume 1 is going at a 500/month clip, while both vol 2 and 3 each sells about one copy per day (~30/month). The one copy a day rate is really really steady, surprisingly so, except during the weekend of Hurricane Irene, when it jumped to 3-4/day. Amusingly, a LOT of people must have been buying Kindle books that weekend because although the sales rate tripled on both books, their Amazon sales rankings dropped! So they must have been seriously outsold by other books.
I don’t know if having the serial still free to read online spurs more people to buy the ebooks or if fewer do because after reading volume one, they just come to the site to read. There were probably a few who would have bought instead of reading on the site, but hopefully when new content starts to flow (at the end of September, at least, that’s my plan) some of those folks will become donors & supporters, or tell their friends who will, et cetera. Giving stuff away has absolutely worked as both a community-building move and as a marketing/sales/pr move. Maybe in these days of online media, the difference between those two things no longer has meaning.
I have no plans to take down the site or previous chapters. Ideally the entire thing will remain free to read in the blog format, while the ebooks will be for folks who want to pay for the privilege of having them packaged nicely for their ereading device.
I don’t rule out doing a print edition at some point, or even selling the print rights to another company, but I wouldn’t want to have to take down the site. Any publisher who is interested hopefully is savvy enough to know that the site is a gateway for new readers, just as a library would be.