I agree with Tarkus. Mozilla's nice but still has a way to go. I'll stick to Netcaptor:
1. All new windows upon up as new tabs. None of this goofy Javascript stuff that launches an entirely new window.
2. User-specified aliases. I type "wcm" in the address bar and it takes me to the wincustomize message board page. I type "au" to go to art uproar. I type "da" to to go dev art and so on. Mozilla has some vaguely similar mechanism but its not a personal, customizable system. Its based off of common set of keywords.
3. When a URL shortcut is clicked somewhere, it displays as a new tab in the current instance of Netcaptor. Unlike Mozilla which either launches a new instance of Mozilla (defeating the purpose of a tabbed browser) or redirecting the CURRENT tab to the the URL in the shortcut (again, defeating the purpose of a tabbeQd browser). So I'm forced to only use Mozilla's bookmark menu.
4. I can drag tabs and reorganize them. I don't think Mozilla can do this.
If Mozilla ever does the above, then I'm sold.
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I went to the mozdev message board and they said you can do all that by modifying a few preferences and installing one of the tabs extensions.