Those are interesting ideas.
MyPage uses the ASP.NET WebParts technology which is not supported on Mono so I have no plans to use it elsewhere in mojoPortal. Its also does not produce the greatest html markup, it uses tables for layout. MyPage is designed to be the same concept as MyYahoo, or iGoogle, or NetVibes ,or PageFlakes.com. Its just a way for users to create pages from content exposed to them in the catalog. There is also a relationship with WebParts and Sharepoint so it may be possible to host Sharepoint WebParts in mojoPortal, though I have not tried it.
I'd like to implement drag and drop layout for the content system at some point but won't use WebParts technology to do it, I'll just use plain old ajax.
Populating MyPage based on tags seems interesting, but it also seems problematic if there happen to be thousands of things in particular tags. Not something I plan to work on any time soon. First I need to implement tagging in general and thats a big job as it is.
Possibly we could personalize content in the email based on user preferences but it seems more simple to have more than one mail list targeted to specific things and the user subscribes to ones that interest them. Newsletter is very rudimentary now and needs more work to get full featured. I'll get to it when I can but its not my top priority at the moment.