Q:

MultiCollider / Site Switcher not showing all sites that I have accounts on

When looking at the MultiCollider drop down I'm not seeing my accounts on Code Review or Area 51.

I could swear I saw my Code Review account there the day I created the account, but since then it seems to be missing.
The only reference I could find on the intended behavior of the MultiCollider:

Your current site appears at the top, along with any relevant meta, chat, and blog links. Stack Overflow gets a careers 2.0 link.
  Immediately below, in a new condensed format (you certainly don’t need
  descriptions if you’re participating in a site already), you’ll get
  a list of all the sites that you have logged into, in order of
  reputation. Finally, you’ll find the full alphabetical site list
  with descriptions, searchable by title, URL, and description.

A:

The site selector only shows a limited selection of sites that you're most active (read: have most rep) on at the top above the search bar.  For example, mine currently looks like this:

The rest of the 63 sites I have an account on don't get shown at the top — if I want to get to them via the sitw switcher menu, I have to look for them in the alphabetical list (or use the search box).
As for why this is done, well, let's go back to that "63 sites" part.  Sure, I might appreciate a convenient link to Graphic Design, Physics, Biology or Academia, all of which I have more than 1k rep on, but if those were all included at the top of the menu, the search box would drop out of sight — and that would be a much bigger inconvenience.  And I'd still be missing out on several sites that I visit pretty often, but don't happen to have as much rep on.
A simple "show more..." link above the search box would be kind of nice to have, though.
And if you think I have it bad, just think of all the poor SE employees who have an account on all the sites...

