Microsoft chose to release Windows Phone 7 for the 2010 holiday season with some key features missing rather than hold it up to get everything in. One of the biggest omissions is the lack of Copy and Paste. They said from the beginning that it would make it into the product, just not in time for launch. The "massive" update in 2011 will surely have this feature.
As to whether or not it will have a lot of other features though is unknown. Microsoft, responding to Walshie's tweet, has put a bit of a dampener on the enthusiasm the tweet has generated. Engadget has the response:
"Microsoft is committed to delivering regular updates to the Windows Phone experience. Our first update will make copy & paste available in early 2011. In addition to this first update, all Windows Phone 7 users should expect to see additional updates delivered in the future as part of Microsoft's ongoing update process."
We'll just have to wait to see what the update ultimately entails. Either way, it looks like Microsoft is favoring multiple smaller updates in the course of Windows Phone 7's lifecycle versus one or two very large updates. That is what the other major smartphone platform makers are doing, so it makes sense for Microsoft to do the same.