Sounds like a pretty minor bump, with Flock going from 0.5.x to 0.5.11, but some really cool new features made it in. The Flickr browser topbar rocks. I mean, wow. That sucker is sweet. And a built-in Technorati info display topbar, to get a quick 10,000' overview of a site as defined by external links. Very handy. They also updated the blog editor to use a local copy of TinyMCE, and it looks pretty darned nice (Categories aren't sorted, though, and no Category search is implemented, making it a PITA to select one of my 304 categories for a new post...) and is FAST since it's local. Feels like a native app. I thought it was a XUL thing at first, until I read the change log.
I'm getting really tired of constantly switching browsers every week, between Firefox, Safari Nightlies, Flock, Camino, OmniWeb, etc... All of this darned innovation is exhausting to keep up with! :-)
As an aside, as I was writing this, Wynton Marsalis' "Quick Ate" was playing on my iPod (hooked up to my TV so I can crank out the music). Evan is up in his room for "quiet time" and he calls down "see it on your 'puter!" - the only time he's heard this song previously was when I was playing the video (on my 'puter) that was included with the album via iTMS. Like 3 weeks ago. Why can't my memory work like that? The iPod has since moved on to play some New Pornographers, so he's gone back to "quiet time."
Update: Just realized how much I miss having bookmarklets in the browser's favorites bar. Flock uses del.icio.us bookmarks to store everything, and I don't have a burning need to populate my account with a bunch of personalized javascripts, nor links to pages within the inner workings of the various web apps I basically live in... The change log mentioned something about private bookmarks, so I'll check that out. But, I don't see a way to have folders of bookmarks in the favorites bar, never mind a way to open all bookmarks in a folder in new tabs simultaneously...