Wow, great feedback, thanks for sharing. I largely agree with you on almost all accounts, but my point was not "OSX sucks", I was saying that "Gnome/Linux have a great UI too". For instance in Gnome there is a concept of "horizontally maximized window" or "vertically maximized window" (both have super-flexible hot key assignments), so when I am working with an application that suddenly spits out a lot of information in a window (terminal is a prime example) I can quickly maximize it vertically and quickly go back. Moreover, there is a concept of "window groups" that allow me to "merge" several windows into one and flip it when I need to: great of debugger/code windows or HTML/Browser or whatever. My point is that OSX simply won't let you do that.

When I'm talking about "virtual desktop isolation", I mean that under Linux, applications running in different desktops don't mix: Alt-Tab list (or Command/Tab in OSX) is separate for each desktop, and an application running in desktop A cannot open a prompt on desktop B (something I see happen frequently in OSX: Skype may have a contact list in desktop A, but it opens pop-ups on desktop B, same applies to safari and numerous other apps). Under Linux each "space" or "virtual desktop" feels like another computer altogether: I often run up to 5 desktops on Linux with 10-15 apps running in them, while on OSX it quickly becomes a huge mess: sometimes I hear the sound of someone having sent me a message via Skype but I can't find the goddamn window - it can be anywhere and Command-Tab list is useless.

Back to del.icio.us issue: no, Gnome does not have it "built-in" but Gnome has a very rich system of plug-ins for its desktop search feqture. The community is quite active and del.icio.us plug-in is bundled as an option with Gnome itself, along with a huge list of others. This is a prime example of where a commercial body (Apple Inc) can't compete with the crowd. And no, delimport does not work: I've tried (along with 3 or 4 other apps).

I am not bashing OSX, in fact I'm typing this words in it right now, all I'm saying is that when in comes to UI, Linux is not behind at all, in fact I believe it's ahead of everybody else in some aspects of usability. It's hard to beat Apple because of their "whole banana" philosophy: MBP+OSX is a great combination of hardware/software, something that Windows/Linux simply can't do.