Recently a URL was posted on Ask Different that looked like this:
Why does it have the "?as=1" at the end of it? I understand that it is part of the workings of the website, but what is its purpose?
I've been exploring since yesterday in response to this comment and have found the following so far:
Some suffixes have since been removed in subsequent redesigns:
Actually, Kevin is correct. It's just to let Stack Exchange's staff know how are things going.
All sites in the dropdown menu have
We slap slugs onto links in places where we're looking for hard numbers about usage. Click through rates, visitors per share, that sort of thing.
It's a decidedly low tech approach that has a couple of benefits.
Offhand, I know we're looking at newsletter links, the site drop down, the hot question drop down, and shared links (Twitter, Facebook, Google+).
The data we collect can be used for figuring out whether certain features are worth keeping around or promoting. Sometimes it's just trying to measure the effectiveness of changes.