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.

Pamir

The “Birthday Bash” free plugin is the perfect solution for small WooCommerce stores looking to add basic yet effective birthday coupon functionality. Automatically send a special gift to your customers on their birthday, making them feel valued and encouraging repeat purchases.
✨ Core Features:
<ul>
<li>Automated Coupon Sending: Send birthday coupons automatically 7 days before a user’s birthday.</li>
<li>Basic Email Customization: Personalize your birthday emails with your store’s logo, a custom greeting, and a message.</li>
<li>Flexible Birthday Collection:
<ul>
<li>Allow users to manually enter their birth day and month in their “My Account” area.</li>
<li>Optionally collect birth day and month directly during the checkout process (including on Gutenberg-built checkout pages via a dedicated block).</li>
</ul>
</li>
<li>Coupon Display: Inform customers about their active birthday coupon directly on the cart page.</li>
<li>Coupon Configuration:
<ul>
<li>Set coupons as a fixed cart discount or a percentage discount.</li>
<li>Coupons automatically expire after 14 days from issuance.</li>
</ul>
</li>
<li>User Restrictions: Restrict birthday coupons to logged-in users only.</li>
<li>Admin Control:
<ul>
<li>Option to make the birthday field mandatory during checkout and in My Account.</li>
<li>Option for users to easily unsubscribe from birthday coupon emails.</li>
</ul>
</li>
<li>Basic Logging: View a simple log of issued birthday coupons within the WooCommerce > Coupons section (via custom meta data).</li>
</ul>

Birthday Bash

Make WooCommerce customers happy by automatically sending birthday coupons. It’s an easy way to boost loyalty and bring them back to shop again.

Blog Birthday vs Birthday Bash