Actually, if you think back to when Gmail appeared, they offered a very high limit (was it 1GB or 2GB to start with?) at a time when 10MB-20MB was common. I remember thinking the exact same thing about Gmail back then as you're saying about Yuku now.

1TB is an enormous amount of disk space, but to be honest, 1GB still seems pretty huge too - particularly for emails, although attachments could use up quite a bit of that space. The problem with the "1TB" of disk space is that Yuku automatically resizes any images above a certain size anyway, so it would take a long time to use up all of the space. It's not like you're a photographer uploading very high quality images (think 10MB per image).

Still, look at Flickr.com - a huge photography community with bandwidth limits but NO disk space limits for subscribers. And they don't scale down your originals. So it's quite feasible to use up a lot of disk space, but most people just don't, because they don't put their entire collection of photos online. On Flickr I've seen photographers with 33,000 photos in their photostream - imagine if they're all 10MB - that's 330,000GB for each of those users. But those users are not the norm - if you look around Flickr you'll see that most subscribers have a few hundred to a few thousand photos.

As image hosting on a message board system, though, 1TB is just not needed by the vast majority - and I'd go so far as to say the entire userbase, unless Yuku suddenly becomes a photography site (not likely).