There’s a growing market for mobile apps designed to help couples stay closer. The phenomenon first came to my attention with the launch of Pair at Y Combinator’s most recent demo day. But since then, I’ve seen a whole bunch of new apps popping up, all seeking to offer up a tight little social network for two. The latest such app to launch is Avocado, which was created by a couple of former Googlers looking for a way to get closer and better organize their life together. It allows couples to create to-do lists and cross items off, upload pictures to share with one another, and send private messages to each other. It also lets users create and send “quick notes” to one another, over and over again, as well as “quick faces,” which swap out common emoticons for unique facial expressions of each partner.

Every developer wants Facebook referral traffic, but not all apps have actions that fit well with auto-sharing, and others might not want to post to Facebook without their users’ express permission. So today Facebook launches a Like action for mobile and web apps. Don’t call it a “Like Button” though, as instead of immediately being one-click, the new Like Action requires a user to give publishing permission to an app first. The Like Action will also generate activity Facebook can turn into Sponsored Stories, the center of its mobile monetization plan.

This notice is to inform you that we will be making a slight configuration change on our core network Wednesday night into Thursday (4/4/2012 11:45 - 4/5/2012 01:00 EST). There should be no service impact during this window.