Publishing Materials Data - Critical issues

For end-users

A familiar, standardized user-interface, ideally a web browser - I don't want to learn a new system
Distributed access - I want to use this from my PC
Data pedigree and context - I don't just want an item of data or a piece of information, I want to understand it and know where it came from. For example, I may want an image linked to explanatory text, or a derived property linked to the source data
Software tools for searching, material comparison, and reporting - I don't just want to see the data, I want to use it
Easy data export - I want to use data in my computer-aided engineering software
Unit system conversion - I want the data in the units that I use
Contributing data to the database via the web - I want to participate in a community

Handling of data in any format - I want to mix varied information and documents: text, numbers, spreadsheets, images, graphs, charts...
Smart linking - I want to be able to connect related information in a simple way that is clear to the user
Access control - I want to expose different data to different users
Security - I only want a specific community of users to see this data
Ease of publishing - I want to be able to add data in a straightforward manner from multiple locations
Analysis and publishing tools - I want fast conversion of data in Excel spreadsheets to published graphs on the web