
You just click on the reply botton on your browser; the subject then says 're: the nice brown sofa' or whatever. Then you ask for you item, and it's always nice if you put a 'please' in somewhere- I give people priority when they say that.
If you're lucky, the person who's offering it will reply to you in your normal in-box. Sometimes people are overdone with replies for a popular item, so they just post a 'Taken' post on the group, something like 'Taken - nice brown sofa, thanks for all the replies, too many to answer individually'
Freecycle is the best thing out - it brings communities together for recycling, for the best reasons. Yes, occasionally you will get a bad penny who is out to make a profit on 'something for nothing', but all the freecyclers I've met have been great people.
Jo