Normal users don't have the ability to give themselves an unlimited number of email aliases. You need to own your own server/domain to do that. Gmail has a nice feature, but it doesn't obscure your real email address and it is trivial to strip away the extra tag.
The issue here I think is that the average mail user needs some kind of filtering language to control their own inboxes.
There is no standardized way to do this, which is a shame. I would really like for their to be a standardized server-side mail filtering language for mail services, where you can take your rule set from one mail server to another.
Personally, I have my own mail server and it has it's own mail filter system and language, but I am not always on the command line with my mail client to modify those filters.
Outlook, Thunderturd/Seamonkey, and other clients have some client-side rules, but those rules don't work if my desktop is offline I am reading those messages on my phone.
I hope in the future well-regarding developers who don't have a private interest will take a look at email again and make the improvements needed to continue to support this standard communication format.
Egos and private-self interest is not what made the internet great, but there is little shortage of it these days amongst us. Where will the Tim Berners-Lees, Richard Stallmans, John Postels of the future come from? These people didn't get rich. We did.