Ok, you caught me! 
A couple questions already came up today as to why their green card tracker result increased, albeit slightly, since yesterday. It was due to a database bug that I fixed late last night. Here is what happened:
We calculate the total number of pending I-485 applications ahead of you using a two-step process:
Step 1: Count all cases with earlier priority dates than yours. If your PD is May 10, 2007, for example, we count everybody with a PD of April, 2007 or earlier. This step will give you the majority of people ahead of you.
Step 2: Count people whose priority dates fell in the same month as yours. Using the above example, this step covers everyone who started their journey in May, 2007. But not all of them are ahead of you! So we estimate the number based on your priority date and how DOS sets up cutoff dates in the visa bulletin. This is usually a small number except for a few months with thousands of people, and your PD is quite late in that month.
The green card tracker result reflects the sum of both numbers.
Because of a software error, however, the May 27, 2011 result didn’t include step 2. If you used the tracker in the past two weeks, you were seeing only step 1 numbers.
The bug has now been fixed. If you check the tracker today, your result may be slightly higher, depending on your exact priority date.
Sorry for the confusion, folks! As always, keep the questions/comments coming. You can use the Contact Us form (on the main site) or this thread if you feel like registering for a free account.
