After flushing my cookies today, I notice that the 'share' link which brings up a box of social networks is not working very well, at least with Twitter.
First, twitter is opened in the same window. After posting, I have to open a new tab and go back to Area 51.
Secondly, if you aren't logged into twitter, the link is not carried through after signing in. Again, you have to open a new tab, go back to Area51, get the link then post it.
If all of this happened in a new tab / window by default, it would not be so noticeable.