Other Changes in Chatter

Smaller changes, such as redesigned email notifications, can improve your experience with Chatter.
Mobile User Context Switching from Emails
Clicking links in Chatter email notifications and digests on mobile devices launch the context-appropriate application, organization, and community.
Attachments in Email to Groups
Users can now include attachments when emailing posts to groups in Chatter. A single email can include up to 25 attachments. The first file attached is included with the post; additional attachments are added as comments. Attachments are uploaded as files in Chatter, then shared with the group. The sender is the file owner.

You must enable this feature for your organization in Setup by clicking Chatter | Email Settings | Allow Attachments via Email.

Reports on Topic Assignments
Users with the “Manage Custom Report Types” permission can create a report type that reveals how topics are assigned. Choose the Topic Assignments primary object, and select from these fields: Created By, Created Date, Network, Record Key Prefix, and Topic. The Network field is available only if Salesforce Communities are enabled for your organization. The Record Key Prefix field indicates the object type (account, opportunity, etc.).