To add to Pewpewarrows' comment, I'll give you a couple of examples of things I do with QuickSilver.
I can never remember the IP address of my work's VPN, so I created a text file on my desktop with the IP as its name. Whenever I need it, I do: Ctrl+Space, ~/Desktop/[IP] to select the file, '.' to treat the filename as text, tab to go to the action part of QuickSilver, start typing "clipboard" and when "Copy to clipboard" shows up, I press enter. It can sound like a lot of steps but it gives me the IP address in my clipboard without reaching for the mouse, without having to open a file or an app.
I also use it for the integration with the address book. I type the name of the contact, select a phone number, tab to the action part and type "skype" to start calling with Skype. Or I would copy it to the clipboard to put in Google Maps…
If you've never used QuickSilver, that might sound too complicated for not much benefits, but it's something you learn over time. And it's not perfect either: I often time use Spotlight as well. (mostly for dictionary and calculator, though I'm sure QuickSilver can do it too :))
> I can never remember the IP address of my work's VPN, so I created a text file on my desktop with the IP as its name. Whenever I need it, I do: Ctrl+Space, ~/Desktop/[IP] to select the file, '.' to treat the filename as text, tab to go to the action part of QuickSilver, start typing "clipboard" and when "Copy to clipboard" shows up, I press enter. It can sound like a lot of steps but it gives me the IP address in my clipboard without reaching for the mouse, without having to open a file or an app.
If you don't mind a bit of drag and drop, a text clipping [1] may be even faster... simply drag the IP address text to the desktop, then drag it back when you want to pull it back in... text clippings make your desktop into a super-clipboard (only downside is the resulting files don't sync over dropbox)
Though I'm mostly-keyboard, I use the mouse where it makes sense, and OSX's drag and drop is a huge time-saver.
Quicksilver is one of those things like learning Vim or Emacs (though less complex), where the not-so-gentle learning curve gives way to a ton of functionality at your fingertips.
QuickSilver: just works, and selects correct thing you might be looking for.
Spotlight: is slow, show all kinds of crap you are NOT looking for. To add insult to injury it also requires typing way more characters to get a hit, and requires several keypresses to select that item, not just return.
I can never remember the IP address of my work's VPN, so I created a text file on my desktop with the IP as its name. Whenever I need it, I do: Ctrl+Space, ~/Desktop/[IP] to select the file, '.' to treat the filename as text, tab to go to the action part of QuickSilver, start typing "clipboard" and when "Copy to clipboard" shows up, I press enter. It can sound like a lot of steps but it gives me the IP address in my clipboard without reaching for the mouse, without having to open a file or an app.
I also use it for the integration with the address book. I type the name of the contact, select a phone number, tab to the action part and type "skype" to start calling with Skype. Or I would copy it to the clipboard to put in Google Maps…
If you've never used QuickSilver, that might sound too complicated for not much benefits, but it's something you learn over time. And it's not perfect either: I often time use Spotlight as well. (mostly for dictionary and calculator, though I'm sure QuickSilver can do it too :))