Well, i abandoned Firefox temporarily because my huge history file takes forever to load and it was getting to the point that it was just not working as a browser on my weak system.  So i figured i’d give Flock another try as a near-Firefox alternative.  I hesitated at the import screen, but chose not to import all my Firefox cruft and started with a clean slate.  It was fine for a bit.  But as soon as i enabled my del.icio.us account Flock started burning at near-100% CPU and was frozen for several minutes.  And it did the same everytime i restarted it.  So i ended up with pretty much the same problem after all.  I was hoping this would have been fixed—the very first time i tried Flock, that same online-bookmarks hang put a bad taste in my mouth.  Not sure if i’m doing something wrong, but this integration just isn’t worth it if gets in the way of browsing.