Tomorrow morning, around 7am ET, we will be launching MailChimp v5.2 (here’s a sneak-peek at the pretty landing page). This is a big one. There are major new social features being added, plus some enhancements to existing features that we think you’ll love. More detailed blog posts are forthcoming, but here are some highlights:

Social Integrations:

1. As was picked up by AllFacebook and Mashable last week, we’re making it easy to integrate the Facebook Like button into your email campaigns, then track your total Likes and subsequent “re-likes” in your MailChimp stats. Email marketers may indeed be tracking our “Like rates” soon. This is not the same as the “share on your social network” links (which we launched back in January of 2009). The Facebook Like button has much more significance for website owners.
2. We’ve created a Facebook App that allows you to collect email subscribers from your Facebook wall.
3. We’re launching an add-on called Social Pro that syncs your email list with the social graph. We’ll show you what social networks your subscribers are on, who’s following you on twitter, rank subscribers by influence, and more. We’ll be posting more details very soon, but you can check out the video here.
4. MailChimp Raplet for the Rapportive Gmail plugin: Users of the popular Rapportive can now see if a contact has opened or clicked any of their recent MailChimp campaigns, too.
5. AutoConnect Templates – If you have an Etsy, Yelp, iTunes, eBay or Amazon profile page, MailChimp can automagically design an email template for you to send to your followers.

New Features:

1. User-agent tracking: We’ll show you what email apps your subscribers use, and even break down mobile vs. desktop apps.
2. Gravatar integration: If a Gravatar exists for any of your subscribers, their photo will appear in their member profile on MailChimp (see: Gravatar Has Just Become a 22 Million+ Strong Social Network). It’s so cool to see actual pictures of your subscribers.

Refinements:

1. Autosave added to more places in the campaign builder process to reduce the “I lost my content, you #$@% monkey!” tweets
2. Campaign content editor window is no longer a tiny sliver of a textarea, but uses a lot more of the screen
3. Pre-built fields for your signup forms: gender, days of the week, months of the year, US stats, and world countries

That’s really just the tip of the iceberg. More features and details will be posted soon. The upgrade is a live rollout, so we won’t be turning off and rebooting the servers or anything (so tracking, signups, etc should not be affected).  Stay tuned!