Virtually every company does backups.

Virtually none of them actually test to make sure those backups are any good.

Please if you do backups, actually do a restore too so you know if the data is good or not.

In an effort to ease the sting of losing its Sidekick customers' data, T-Mobile is crediting a month's worth of data service to its Sidekick users, and issuing US$100 T-Mobile gift certificates to users if their data isn't recoverable. The cell service provider recently revealed that Microsoft's Sidekick cloud servers lost all of their data, leaving many users without their contacts, calendars and other personal information.

This particular story goes on to say

"We have made significant progress this past weekend, restoring services to virtually every customer," T-Mobile said. "Microsoft/Danger has teams of experts in place who are working around-the-clock to ensure this stability is maintained."

Presumably those are not the same experts that led to the data loss.