The value proposition offered by gmail isn't yet good enough to convince users of hotmail and yahoo over. In particular ever person under 18 that I've met in the past year or so seems to have msn chat and use it constantly.
Here's how they could tip the value proposition.
1) More user names. I've used the same anthony_barker address with hotmail and yahoo for years and I when I got gmail it was taken. This pissed me off. Why not offer the naming convention of firstname.lastname@state.country.gmail.com. Eg john.smith@ca.gmail.com or john.smith@fl.us.gmail.com.
This gives a name that everyone could remember without writing down. My friend john smith in Florida john.smith@fl.us.gmail.com. looks a lot better than smithj0128@gmail.com.
2) Open chat which gets logged in your gmail account using Jabber protocol or similar. If they could convince phone manufacturers to integrate this into the phones this would be a killer app. Another step would be to integrate chat into the browser/gmail. Sort of like what Lotus Notes 6.5 does. You can see if the person you are emailing is online or available and can click on their name to launch a chat session. Yahoo does this as well.
3) Notepad functionality. Yes it is a trivial feature in yahoo mail. But I use it extensively.
4) Access to your documents from anywhere. This would appeal to students who need a place to store and backup documents they are working on. Workers who want access to a document from work but their company isn't set up to share documents. They could create a plug-in to MS Word that allows you to "Save to Gmail". I've created similar apps that use MS Vbscript XMLHTTP to download or post binary data. I've also created similar apps in python. This would give sort of stripped down Sharepoint functionality to users.
5) Sync your address book with your phone. MSN requires outlook/outlookexpress, Yahoo requires 3rd party software. Why not build a plug-in right into the browser that does it?
6) Calendar which can integrate with other apps and uses open standards. Seems like they are working on this one.
