I used to be a Freecycle mod. It was something I thought I'd be good at. I am technically literate, had time to spare and wanted to do "my bit" so to speak.
One of the biggest problems in my mind is the entire system is based on Yahoo groups which is well...crap. Once you've approved someone to post directly, there's nothing stopping them from posting repeated wants. Yes you can put them back on moderation but its effectively locking the door after then horse has bolted.
When a member posted abusive messages directly onto the group then later directed to myself, I banned her. She joined as someone else. Banned her, joined again. etc. In the end it was easier to keep her on the site and just moderate her posts rather than play cat & mouse.
Also, as a mod I have to say that there are huge variations in how groups are moderated. Some are strict and run by power nazi's, other's were pretty laid back. There is a rulebook and even a UKModsquad which was meant to harmonise this but like most member's, I often wondered how many moderators had read the guidelines. There was no consistency.
For me the few ruined it for the many. Time & time again you had certain individuals who would post wanted's for high value items. I remember seeing posts for Xbox's and Nintendo DS's. The one which took the biscuit though was the lady who wanted a sandpit. Not just any sandpit, she included the page number in the Argos catalogue of the one she wanted.
The final nail in the coffin for me was when the UK "leadership" fell out with the US "leadership" resulting in UK lot deciding to leave and go there own way. Quite why they fell out was beyond me. I thought we were all there to save things from going to landfill. I took the opportunity to resign.
I still think Freecycle is a fantastic idea but it really needs to move with the times.