These new features put me into thinking about GMail's strengths, especially in mobile use. One nice feature is the Push Mail feature that works just great. In fact it works so well that sometimes I have wondered could it be used as a cheap replacement for SMS messages. As everybody knows, SMS's are great way to send user quick information, but the drawback is that every message costs real money to the sender. If you send lots of messages, that will have economic importance although cost for one single message is negligible.
Some time ago I was looking for a solution that could alert me by SMS when some important RSS feeds are updated. I can understand that the lack of these kinds of solutions is just because nobody wants to pay the price of sending SMS messages to users. My idea was essentially not about receiving SMS's, it was about receiving alerts to mobile terminal and that requirement could quite nicely be implemented with mobile GMail. What this would mean is that Google team should add feature to Reader that would allow user to request an email alert when an important feed is updated. If user wants, he could redirect an update message to his GMail inbox and if that account/folder is subscribed to mobile phone, we would have a free RSS alert without any SMS's.
BTW: did you know that you can append tags to your GMail address, just write +
after your email address, like email@example.com. After you have tagged your address like that, it is easy to create filters and it is also a nice way to track who has leaked your email address to spammers.