Whilst development has been focused on rolling out new system features like the new messages feature, the infrastructure changes have been looking at protecting data further between your web browser and our servers. At present, everything between you and us goes via SSL (Secure Socket Layer), at the same standard used to protect credit card payments. Even for just loading images. In some instances/regions, we have also use a content delivery network to help speed up the pages - and that also goes through the SSL service.
About a week ago, we started forcing all traffic through SSL (going to http://www.kablam.net/blah would automatically redirect to https://www.kablam.net/blah), which we've been doing a via Kablam's underlying software (Encore). We've now started doing this a little bit further up the chain by implementing HSTS - a feature all modern browsers support to help us make sure that nothing slips through the cracks and goes unsecured.
So what changes for you? nothing much. As long as you're on a modern web browser and a modern OS You'll still be able to use the site like you did yesterday, last week.etc