There were some new announcements just made for SharePoint Online that I was really excited to see that are now supported. Specifically the Content Search Web Part and Cross-Site Collection Publishing are now supported in SharePoint Online. Why is this exciting? With both of these features now available, organizations will be empowered to create more robust publishing sites in SharePoint Online.
The Content Search Web Part (CSWP) uses SharePoint search to find content and then publish the results on the page. In most cases, end users do not even know that search is being utilized to find documents, list items, videos, etc. to be displayed on the page. Using the CSWP is a much more efficient want to display content on publishing pages.
What is just is as exciting is the addition of the Cross Site Publishing feature to SharePoint Online. Publishing features have always been available in SharePoint Online so that items and documents must be published to be seen by end users. Now with Cross Site Publishing you have the ability to create an Authoring Site Collection where you can centrally define content (lists and libraries). Then you can add CSWP web parts in other site collections that can present that content. This can be a very helpful solution if you are managing many site collections yet there is common content that you want to manage and publish centrally.
Here is more information about the announcement - http://blogs.office.com/b/office365tech/archive/2013/10/29/search-innovations-for-site-and-portal-design-in-sharepoint-online.aspx.