I thought this was definitely blogworthy, rather than just going out in a tweet.
There are solutions to fix Safari always opening another window for new links, but in Safari 5, you can make this choice through Safaris built in preferences.
So If you’re a fan of tabbed browsing,head over to your Tab Preferences (Safari > Preferences > Tabs) and select Always from the drop-down menu that says Open pages in tabs instead of windows.
Once you’ve done that you will get a pop-down menu that asks if you’re sure you want to change this setting. By selecting Always Create Tabs, Safari 5 will open everything in new tabs instead of new windows.
And if you accidently close a tab, Command+Z reopens the tab. Magical.
In my opinion, this should be a default setting.