Facebook IDs

Here’s an interesting link about how Facebook IDs used to be assigned:
http://www.quora.com/What-is-the-history-of-Facebooks-ID-numbering-system/answer/Justin-Mitchell

Back in the day when you had to have a college email address to sign up for Facebook, Facebook IDs were assigned by the network one first registered with. Each network had a certain prefix that appears at the beggining the Facebook ID. For example, the prefix for Carnegie Mellon was 48, so everyone who started with the Carnegie Mellon network has an ID of 48xxxxx.

I was bored one day and tried to determine which college got which prefix. I soon found that it goes up to at least 3000, so I gave up after 100 colleges.

0 Harvard
1 Columbia
2 Stanford
3 Yale
4 Cornell
5 Dartmouth
6 UPenn
7 MIT
8 NYU
9 BU
10 Brown
11 Princeton
12 Berkeley
13 Duke
14 Georgetown
15 UVA
16 BC
17 Tufts
18 Northeastern
19 UIllinois
20 UF
21 Wellesley
22 Michigan
23 Michigan State University
24 Northwestern
25 UCLA
26 Emory
27 UNC
28 Tulane
29 UChicago
30 Rice
31 Washington University in St. Louis
32 UC Davis
33 UCSD
34 USC
35 Caltech
36 UCSB
37 Rochester
38 Bucknell
39 Williams
40 Amherst
41 Swarthmore
42 Wesleyan
43 Oberlin
44 Middlebury
45 Hamilton College
46 Bowdoin
47 Vanderbilt
48 Carnegie Mellon
49 UGA
50 USF
51 UCF
52 FSU
53 GWU
54 Johns Hopkins
55 Syracuse
56 Notre Dame
57 Maryland
58 University of Maine
59 Smith
60 UC Irvine
61 Villanova
62 Virginia Tech
63 UC Riverside
64 Cal Poly
65 Ole Miss
66 Mich Tech
67 UCSC
68 Indiana
69 University of Vermont
70 Auburn
71 University of San Francisco
72 Wake Forest
73 Santa Clara
74 American
75 Haverford
76 William & Mary
77 Miami University
78 JMU
79 Texas
80 Simmons
81 Binghamton
82 Temple
83 Texas A&M
84 Vassar
85 Pepperdine
86 Wisconsin
87 Colgate
88 Rutgers
89 Howard
90 UConn
91 UMass (Amherst)
92 Baylor
93 Penn State
94 Tennessee
95 Lehigh
96 Oklahoma
97 Reed
98 Brandeis
99 Trinity College

One interesting thing to note is that there are some prefixes that don’t have any users. For example, I couldn’t find any IDs starting with 131.

These days everything is different. User IDs are 64-bit integers and it seems that people who sign up now get 15 digit Facebook IDs. I can’t tell if IDs are given out sequentially, but if they are, it means there’s well over a billion accounts. According to Facebook, there are at least 500 million active users, so either there’s a lot of inactive accounts or maybe objects get assigned from the same pool of IDs or  there’s some other way IDs are assigned.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s