script (featured in December)
Optionally Anonymised Short Links
Resurrected Anonymize short links userscript allowing the "share" button to operate anonymously (natively, it appends the current user id to the short post link). The updated version can also be persistently configured to use either the anonymized or native links.
Might not look like much on the first glance, but it saves a bunch of trouble when adding links to posts where the current user id would be inappropriate (various FAQs, for example).