There appear to be some issues with Foursquare checkins at the moment. I noticed it when I was on my way home and reported it to their help forum. I also tweeted about it but have yet to see any specific acknowledgment from the company yet.
It seems that checkins are counting... sort of. I checked into two places on my way home. Ousted someone for mayorship of the first venue. And then had to create and check into the second. Both of my checkins show up on the venue pages and I was awarded that mayorship.
But those checkins are not showing up on the "feed" on my profile page, my history page, or registering on my stats page. I can't confirm if I got points for them or not (frankly don't care) but some users are reporting they are not receiving points. Even more are reporting that they're getting "this is your first time" messages for that venue - when they shouldn't.
I think it's safe to say something is borked. Hopefully they're on it... Will update if they post any info.
UPDATE: Just got an email that I was ousted as mayor of the venue that I just ousted someone else from. That is not mathematically possible. The venue page though still shows me as the mayor. Something is seriously f'd.
UPDATE 2: So that ousting of my mayorship apparently went through - even though it is not possible. The venue page has changed to reflect the new (previous) mayor. Very strange.
UPDATE 3: Believe there are scattered reports of checkins starting to show up for some people. Nothing yet for me, but I hope this means they're working on it!
UPDATE 4: Still nothing resolved for me. A few more people starting to see their checkins show up - but not me. Checked into the gym tonight too and that also does not show up in my history. Will have to check in the morning.
UPDATE 5: The morning after. My two checkins this morning are showing up correctly - but still nothing from last night. I'm wondering if this is "fixed" but we just won't get those back?