Brett Tomlinson did an extensive analysis and charting of BM's data, which you can read here:
http://sunrisecodeworks.com/BookMoochStatistics.html

One thing Brett did right is to only count active members in all his stats. That's the equivalent of "adjusting for inflation" and makes his numbers much more relevant.

There are six charts in particular that I find interesting. I'm reproducing them here with Brett's comments and then my comments after.

When a user adds a book to Inventory, they can add optional Condition Notes to describe the condition of the book. Not all books offered on BookMooch are in pristine condition, and many users prefer to request a book whose condition is known. Condition Notes have been provided for about 30% of the books in users' Inventories. This percentage has not changed significantly over time.

I was surprised that condition notes are supplied as often as this. My guess is that the majority of users don't supply condition notes, but that the most active, veteran moochers do, and that these veterans have larger-than-average inventories, thus bringing this percentage up.

This has diminished slightly from a high in February 2008, from about 40% to 35% of books having condition notes, but seems stable since 2009.

One of the strengths of BookMooch is the ability to trade books with people in other countries. A domestic transaction occurs when the book Giver and Recipient reside in the same country. An international transaction occurs when the book Giver and Recipient are in different countries. Presently, 80% of transactions are domestic -- 68% are US-to-US and 12% are within other countries. 20% of transactions are international. The proportion of non-US usage of BookMooch has been growing slowly over time.

I was happy to see that both International mooching (ie, mooching across borders) as well as use of BM outside of the USA are both growing.

This chart shows the (average) number of books received per active user per month. Although there has been a dip in their number, the active users continue to receive books at the same rate.

It was interesting to see that the average BM member trades 1.5 books per month and has been pretty stable at that level.

82% of books received by users come from outside BookMooch. The remaining 18% are books that have been previously-received from a BookMooch user, read, and re-sent

One of the stats I've thought about adding to each member's bio page is the amount of "regifting" they do, which I define as "giving via BM a book that you received via BM".

That's why I was interested to see that about 1 in 5 mooched books is a regifting. I do wonder how that works out in terms of demographics: if certain members do most of the regifting or it's a broad based phenomena.

I've also thought about the occasional "nag" to people who mooched a very in-demand book over (say) 6 months ago, letting them know that lots of other people want to mooch the book, and it'd be great if they read it soon and regifted it. Just an idea...

For the purposes of these statistics, a user is considered to be "Active" at a certain point in time if they have logged into BookMooch at least once in the 60 days prior to that point in time. If the user has not logged in within 60 days, they are considered to be "Inactive". The 60 day cutoff is somewhat arbitrary. At present on BookMooch, if a user stops logging in, then eventually their account will be suspended, and the user (and their Inventory of books) drops from view. But the account is still intact, and the site makes it very easy for a lapsed user to return to BookMooch and to reactivate his/her account unchanged. The chart shows a decline in active users in 2010, down 36% from its peak in September 2009. This decline is puzzling. The BookMooch site remains healthy and has received frequent incremental enhancements over time; its members are engaged and for the most part contented. External factors may be responsible. One possibility is that the drop in activity in 2010 is a (delayed) reaction to the global economic recession which occurred from late-2007 to late-2009, as fewer users could afford the postage to send books. The opposite possibility is that the recession triggered a surge in activity from late-2007 to late-2009, as people bought fewer new books and used BookMooch instead. If this is the case, then 2010 isn't so much a decline, as a reversion to prior trend, when the economy began to recover and the bubble of thrifty users subsided.

I brought this up with Mark (my admin of admins) and he thought that possibly that 2009 hump might be due to a large amount of fraud that was tried in 2009, some creating as many as 500 accounts, that the admins successfully shut down. Perhaps.

Another factor is that BM use has a seasonality to it, and we always drop way down in the fall of each year, and jump back up after the new year.

Here is a chart I made, of mooches per day (click on the chart for a full size version).

A few things I'll note about this chart:

1) you can see clear annual seasonality, with the fall of each year experiencing a 50% decrease in use, with the lowest BM use right before the New Year. Usage then spikes back up to normal levels.

2) Nonetheless, you can see a clear 15% to 20% decrease in mooches per day in 2010 (1500/day) vs 2008 and 2009 (between 1800/day and 2000/day)

So, from these charts I do think that 2008/2009 was the peak of BM usage, and that 2010 was overall slower.

However, BM is still handling about 550,000 mooches per year, which isn't too shabby.

I have some ideas for improving things a bit, that I'll be detailing in future blog posts.

-john

If you compare mooches-per-day with the number of listed books, you find that they are correlated. Mooches per day are about 0.4 % of listed books, and that hasn't changed much in the life of the site.

Therefore, mooches are decreasing because people are adding fewer books (perhaps there are so many points around that there are less incentives to enlarge the inventory, or maybe it's the increases in postal costs).

If point inflation is occurring, then eventually there will be too many points chasing too few books. If I have a surplus of points, then each point has less utility to me. I will probably mooch books that I otherwise might not. Then that book languishes at low priority on my to-be-read shelf, out of BookMooch circulation likely forever. In the extreme, if points become way too abundant, then people could start mooching books for other reasons than to read them, e.g. just because they like the covers, to cut them up and make ransom notes, etc.

A little point inflation is probably OK, but high inflation (or deflation) can hurt the BookMooch ecosystem.

From the general tenor of the comments it seems that everyone else is waiting for someone else to start listing more books first. And that people are in the current economic climate becoming less interested in swapping books on an equal point or a like-for-like basis. This is frustrating but I personally find more value in swapping used books for books that I want than in trying to sell them for pennies plus shipping and then buying books online for pennies plus shipping. I also find it incredibly frustrating that the majority of US users on this site will not send internationally, and that they do not understand how proportionally cheaper it is to do so with the US postal service as compared to anywhere else in the world (I am an American who has lived outside the US for 12 years). But everyone has to manage their own finances.

I would be happy to spend 3 points to mooch internationally if that encouraged other people to send more internationally. I am not sure if removing the .1 point for marked a book as received is a good idea, as this is not always done automatically. But I wonder if removing the .1 for listing a book might work better, as you do get the points for sending them, and this might help mitigate the problem of overwhelmed new joiners over-listing at the start and then disappearing.

As ever, I am very impressed with the good work you continue to do with the site, John, and am sure that we will be in rude health again soon.

my wishlist is getting smaller and smaller, because the good ones i want dont seem to be put on bookmooch, and the ones in the past i would have been prepared to gamble two points on, i can no longer afford to do.

waaaaaaaaaaaaaaaaaaaaaaah........
i am no longer a happy moocher.

anyone got points to give away or sell?????
hmmmm, bookmooch might find itself facing a black market for points!

recently someone mooched a heavy book from me, i told her it wasnt worth it for me to send the book to her, due to postage being so expensive and the book being heavy...
when she offered me more points for the book, my ears started to prick up!!! that would be fair in my eyes. more points for a heavy book.

a while ago, i was desperate for more points, and put all my much loved books on bookmooch.
they went quickly. i used up the points to get books i wanted to read, which are no longer popular.
now i am stuck with them - no one else wants to mooch them, plus, i am left with all the other rubbishy books on my inventory that no one wants to mooch....

sorry bookmooch, i am slowly becoming disillusioned, if i cannot earn points somehow, i cannot play :(