There is a lot of disinformation about the Libertarian Party's membership categories floating around the Net.
One of the weirdest periods in LP history was the time in 2006 when a proposal was introduced to place annual dues at "zero".
The truth is the LP has --always-- had a "free" membership category. Since its inception. In 1972.
The "adoption" of "zero dues" in 2006 didn't implement zero dues because it was already in force. "Zero Dues 2006" was a harebrained idea that only changed the formula for delegate apportionment to LP national conventions. In other words, it was all about re-arranging deck chairs on the Titanic's butt.
I have some institutional knowledge of the "free" membership category.
I was an employee at LPHQ (1989-1993) when we were still offering "Instant Member" cards in bundles of 100 via the LP literature sales catalog. It was a simple postcard with a tear-off part that you kept, which was a wallet-card sized thing. It said what any membership card would say, had a place for you to sign it, and the back side had the statement of principles.
The part you didn't keep was a standard business-reply post card. The membership statement was there with a place for you to sign it, and of course it had space to enter name, address, and other contact info. Being business reply, it was even free for the signer to mail.
After several years of pushing the "free" memberships, however, the LNC at the time took a look at the effectiveness of marketing the "instant member" category -- and determined that normal prospect lists (ie names gathered at gun shows and college fairs and the like) had a better "conversion" rate than the "Instant" names. As a result, the LNC decided to stop marketing the category.
You could still join as a free member, but other than filing the signature in a portable file box with the signatures of others and noting on the national LP database that the person had signed, free members were not pursued further. As stated, their response rate was extremely low. And LPHQ no longer marketed it as an option.
[As an aside, in 2006, LPHQ staff revealed that their experience was the same in the first months of 2006 under the so-called "zero dues" regime -- free members generally don't ever wind up donating to the Party. I suspect few free members (if any) volunteer, either.]
Throughout the nineties, there were still a few people who took advantage of the ability to recruit free members. I did so (normally only with people I suspected I *personally* would eventually convert into donors). The last "signature only" (ie free) member I recruited and submitted to LPHQ was 2006; in January. By February, I had collected a donation from him.
I have a copy of one of the last national membership reports that now-departed LPHQ staff distributed in April of 2004. These reports counted all the people who had ever signed the LP membership pledge as of the report date.
On the archived report mentioned above, there were 19,276 people who had signed & paid; 69,831 who had signed and paid at one time but who had "lapsed", and 26,294 FREE members. These 26k free members were "lost" by LPHQ:
When Geoff Neale put LPHQ on the new Raiser's Edge database as of 09/14/2004, he failed to retain the signature status of the Non-Contributing members (the 26,294 number). LPHQ still has the names on the database, just no signature flag. I have suggested to current LPHQ staff several times that they fire up the old database and recapture those signature flags, if only to improve accuracy, but they have not done it so far.
In any case, if you take the number Shane Cory reported in 2007 as having signed (105,000) and add the missing 26,294, at that time (2007) there were actually over 131,000 people who have signed the LP's pledge. Every one of them save for the very few who have renounced their pledge, is a "member" -- just not necessarily a "Sustaining" member. Since that report in 2007, doubtless several thousand more have signed the pledge, so I suspect the number of signed members is close to 150,000 now.
The LP uses dues-paying members internally, as it should. The Democrats and Republiboobs don't EVER reveal how many donors they have!
Externally, as with media releases and the like, HQ should report either everyone who ever signed the pledge (the 150,000), OR registered Libertarians. I've actually been trying to get all Libertarians to do this for a long time. It is entirely accurate to state that "150,000 Americans have signed the Libertarian Party's membership pledge", and it sounds a hell of a lot better than "12,000...".
In fact when I was doing a lot of radio interviews, when asked how many LP members there were, my answer was always "there are over a quarter-million registered Libertarians in the dozen-odd states where it is legal to register Libertarian." This got it into the discussion that there were many more Libertarians than could fit into a phone booth -- and at the same time slip into the conversation that registration is discriminatory in many states. It was bait which most of my interviewers managed to catch and bite, giving me an opportunity to discuss our Soviet ballot access laws.
But when talking to my fellow members, I always use the number of "current" donors.