wiki page: http://www.mongodb.org/display/DOCS/Backups
docs page: http://docs.mongodb.org/manual/administration/backups/

new info put in:

• warning: don't just copy dbpath files, esp with writes and
  journaling disabled

• not explicity stated - should be

• match backup strategy with operational workload - don't overburden
  your system resources

• not explicity stated

• File system snapshotting using SAN/lvm

• stated

• use secondary members to backup from instead of primary members
• use fsync + lock

• stated but not with secondary

• shutdown and copy dbpath

• not stated

wiki diffs:
http://www.mongodb.org/pages/diffpages.action?pageId=1474863&originalId=42927550
http://www.mongodb.org/pages/diffpages.action?originalId=42927548&pageId=42927550