This is a yahoo problem, and is effecting all yahoo groups and members who have @yahoo.co.uk addresses. Yahoo are working on this issue.
See here for more details
The Reading (UK) Freecycle group is open to all who want to "reuse" their clutter rather than throwing them away.
Freecycle groups match people who have things they want to get rid of with people who can use them. Our goal is to keep usable items out of landfills and to encourage community involvement in the process.