"We're happy to now support uploading high-definition (HD) videos, up to 720p, from Picasa to Picasa Web Albums. Whereas before you could upload, store, and share videos shot in 240 or 360p, now you can do the same for your 480p and 720p (HD) videos too."
Here's an example of HD video uploaded to Picasa Web Albums. It's less than 3 minutes long and it uses almost half of the free storage quota.
Unfortunately, Picasa Web's new feature would be much more useful if you could upload videos from your browser. Right now, you can only upload videos from Picasa.
While YouTube lets you upload videos up to 2 GB, Picasa Web's free storage quota for all your photos and videos is 1 GB. Of course, YouTube lets you upload videos without installing an additional software.
Another issue is that Picasa Web Albums doesn't offer per-file permissions, so you can't share a video without sharing the entire album.
These are just some of the reasons why YouTube is a much better service for sharing videos than Picasa Web Albums.