Are you an Office365 professional? Here is my list of useful links. Feel free to add more in the comments!
Automatic SharePoint Online Site Collection Storage Quotas http://blogs.office.com/2014/08/18/sharepoint-online-simplifies-storage-management/
Office 365 Development Roadmap http://office.microsoft.com/en-gb/products/office-365-roadmap-FX104343353.aspx
What is One Drive for Business https://support.office.com/en-US/Article/What-is-OneDrive-for-Business–187f90af-056f-47c0-9656-cc0ddca7fdc2?ui=en-US&rs=en-US&ad=US
Office Blogs http://blogs.office.com/
Office Visio Stencil’s: http://www.microsoft.com/en-gb/download/details.aspx?id=35772
Office 365 Jump Start (Small Business) http://www.microsoftvirtualacademy.com/training-courses/administering-office-365-for-small-business-jump-start
Free eBooks incl SharePoint & Office 365 http://blogs.msdn.com/b/mssmallbiz/archive/2013/06/18/huge-collection-of-free-microsoft-ebooks-for-you-including-office-office-365-sharepoint-sql-server-system-center-visual-studio-web-development-windows-windows-azure-and-windows-server.aspx
End User Training Resources for Office 2013 and Office 365 http://technet.microsoft.com/en-gb/library/jj871004(v=office.15).aspx
Security – Office 365 Trust Centre http://office.microsoft.com/en-gb/business/office-365-trust-center-cloud-computing-security-FX103030390.aspx
SharePoint Online Limits & Boundaries: https://support.office.com/client/SharePoint-Online-software-boundaries-and-limits-8f34ff47-b749-408b-abc0-b605e1f6d498
Exchange Online Limits https://technet.microsoft.com/en-gb/library/exchange-online-limits.aspx#MessageLimits
Administering Office 365 for Small Business Jump Start (Microsoft Virtual Academy)
I’d also highly recommend the MS Press Book – SharePoint 2013 Plain and Simple ISBN 978-0735667006 (which you can buy on-line at MS Press Store as a PDF.
Or use the Help in Office365 from the admin pages – it’s actually VERY good
External Sharing (Ignore the product advertising in section 4) http://en.share-gate.com/blog/ultimate-guide-deal-with-office-365-external-sharing
Setting up an eDiscovery Centre https://support.office.com/en-us/article/Set-up-an-eDiscovery-Center-in-SharePoint-Online-A18F8975-AA7F-43B4-A7D6-001D14744D8E and https://support.office.com/en-us/article/Plan-and-manage-eDiscovery-cases-D955AEB8-0D48-4291-A8E2-F3B84F17943F?ui=en-US&rs=en-US&ad=US
Office365 ITPro Yammer Network https://www.yammer.com/itpronetwork (see also https://blogs.office.com/2014/03/06/introducing-the-office-365-it-pro-network/)
