Terry Chay

<a href="http://terrychay.com/wordpress-plugins/blog-birthday" rel="nofollow ugc">Plugin Homepage</a>
Inspired by @TwBirthday on Twitter, this shows a simple message in the admin panel on 
their blog birthday.
“Happy 3rd Blogger Birthday! You’ve been around since 11 August 2008.”
“Happy 7th Blog Birthday! The first post on this blog was on 19 November 2004.”
“Happy 1st Blog Birthday! This blog was first registered on 23 July 2010.”
Caveats: 
– Old WordPress admin accounts have a registration date of 0000-00-00 and never have a 
 blogger birthday. 
– Blog registration starts when you turn on WordPress multisite. If you did this, the 
 date may be off. 
– First post assumes that there a post_id=1 and uses the date off that.
<h3>Future Features</h3>
<ul>
<li>Add ability to change the blogger birthday if blank</li>
<li>Add ability to change the blog registration date if first post is different.</li>
<li>4567890012345678900123456789001234567890012345678900123456789001234567890012345678900</li>
</ul>

Blog Birthday

Show a user a notification on their blog birthday.

omarke85

This plugin will add additional fields in the profil of a user, they can fill in there birthday, choose if they want to share it and if they want to show there birthday. 
When saved, the system will generate a ICAL-file that can included in many calendar programs/plugins.
As admin you can see an overview of all birthdays, with upcoming, passed and with some info about, how many registered birthdays, the oldest, youngest, average age.
<blockquote>
<h4>Upgrade from 0.1.x to 0.1.4</h4>
If you upgrade to 0.1.4 please run the “rebuild birthdys”-script. This because of changes in storing files on the system. 
 When using 0.1.6 and you changes an options the rebuild will be done for you.
<h3>Caution: in version 0.1.3</h3>
For some reason there is 2 breakspaces in the wp-birthday-users.php at the end. Delete these to let the plugin work. (I try to fix it later)
</blockquote>
Version 0.1.7 introduce the posibility to show a widget on your page. This will show you a widget with the users whos birthday is today, and you can choose to show upcoming and past birthdays (and how many of it), also a downloadimage with to the ical.

Blog Birthday vs WP Birthday Users