WordPress' quantum leap: from 50 MB to 3 GB

I've wondered before why WordPress limited users to 50 MB of space in their blogs. I guess they were wondering, too, because they've increased that limit to a whopping 3 GB:

... everyone’s free upload space has been increased 60x from 50mb to 3,000mb. To get the same amount of space at our nearest competitor, Typepad, you’d pay at least $300 a year. Blogger only gives you 1GB. We’re doing the same thing for free.

Our hope is that much in the same way Gmail transformed the way people think about email, we’ll give people the freedom to blog rich media without having to worry about how many kilobytes are left in their upload space.

How are we able to do this? Over the past year we’ve developed our file infrastructure, replication, backup, caching, and S3-backed storage to the point where we don’t feel like we need to artificially limit what you folks are able to upload just to keep up with growth. We’re ready for you. :)

What about the space upgrades? They’re still important. You still need a space upgrade to upload certain file types, like movies, and we’re also increasing the limits of the paid upgrades, so if you bought a 1GB upgrade before it now adds 5GB for no additional charge.

First of all, I'd like to find out what they mean by "certain file types." Second, I think we can count the days until the Google-owned Blogger matches this. (Blogger stores your uploaded images in Picasa, and the limit for a free account remains 1 GB.)