What is a good way to generate a set of (relatively) short "invitation codes"
104351
Unique random string generation
47255
How to generate a GUID/UUID?
45731
Spam iCloud Calendar Invitations
122389
How can I generate a list of all possible permutations of several letters?
77365
Generate all possible n-character passwords
34466
Encrypt IDs in URL variables
154985
How do I post code in chat?
7761
How to add multiple attachments to an email template?
86962
What is the best Java email address validation method?
48835
How do you set requirements (such as minimum length) on passwords?
111320
What's the easiest way to generate code dynamically in .NET 4.5?
83252
Spread letters to a given length?
113242
How many ways can you create a password of 10 characters long that has at least one lowercase letter (a-z) and at least one number ($0-9$)?
9064
Is it a good practice to show a sign-up or registration form as seperate parts rather than in one go?
72516
How to generate the random default "gravatars" like on Stack Overflow?
150979
How do I create a URL shortener?
60527
How to style emails?