My list of useful links:

• PeWu - OSM History Viewer - for individual nodes/ways/relations
• Achavi - Changeset Viewer

• Resultmaps - Changeset Visualisation

• Resultmaps - Changeset Discussions - UK
• Resultmaps - Suspicious Changesets

• tyrasd - changes in last 30 days

• Resultmaps - UK Notes

• Talk-GB mailing list
• UK Community Forum
• UK Quarterly Project - wiki
• UK road signs tagging - wiki
• Robert Whittaker’s OSM Stuff
• Solar panels progress
• Speed limits mapped