One service the usage cap-happy broadband industry will be certain to threaten is online file backup.  Consumers who don’t know any better can easily configure software to back up entire hard drives to a remote hard drive, blowing through an online usage allowance in a matter of days.  Even usage allowances as large as Comcast’s 250GB per month are no match for today’s super-sized hard drives.

So it comes with a bit of irony that Comcast has quietly launched its new Secure Backup & Share service, “powered by” Mozy.

Every Comcast broadband customer will soon be pelted with promotions for the new free add-on, which will initially provide 2GB of storage space.  The free version is enough to backup small collections of music, photos, and documents, and probably won’t hurt your allowance too much.  But Mozy gets to up-sell customers to their much-larger capacity plans right from the home page.  A year’s worth of 50GB of storage costs $50.  Get 200GB of storage space for $100 a year.

Exceeding 250GB of usage per month, with or without the service, will potentially get you a warning letter and then an account suspension.

Bonus points to you if you can find the 250GB usage limit disclosed on the home page for the service.

For providers who try for far lower usage allowances, or charge up to $2 per gigabyte after exceeding them, an online file backup service could make your provider’s day once they send you the bill.