"Many B2C companies go viral by convincing current users to upload their address books and email their friends."
This is just 'legitimized' spam IMHO.
If your product is that good, you don't have to "convince current users" to help you spam... If you make your product really well, people will market it for you, because they like it and want to tell their friends.
Actually, it's not spam at all. It's just a system (let's not go down the "evils of giving someone my email user/pass" road again) that allows users to more easily send to their contacts.
To look at it another way, if you like our widget.com site, we at widget.com are trying to make it as easy as possible to tell your friends. Re-entering your contacts into our system manually is such a pita, that almost no one does it. I don't know about you, but I have never received spam from MySpace, Facebook, LinkedIn, or Yelp. I have received invites from friends/associates/folks I kinda know. This is not spam, this is email from a someone I know using a different sender. Is it always welcome? No. Do I really mind it? No. If you do, you should have a filter on your mail that trashes all mail from addresses other than those in your contact list.
We all know that the centralized contact model with API's and public/private keys would just plain rock, but it's not here yet, and companies are just trying to live with what we have (long enough to get their next round).
Ok, and one more thing - for those of you who try to send emails, this post is a nice summation of the things you should do, have to look out for, should know about, and the sites you need to visit to improve the chances of your legitimate messages getting through.
Your definition of spam seems to be dependent on knowing the sender. I disagree completely with that definition. I receive quite a bit of spam from facebook, all under the guise of coming from my friends. More likely they have been told they must invite more people to unlock secret features (Probably to enable their virtual frog to grow wings or something).
Duping/bribing users into giving you their address book, so you can spam their friends, is not a good business practice IMHO.
I do agree though. If you have a legitimate reason to email people who have opted in, or expressed a direct interest, some of the sites in the article are useful.
Let me clarify. Spam as defined as unsolicited bulk mail/messages. Often folks even throw the work "indiscriminate" into their definition. I don't consider someone that I know actively sending me an invite to something they find useful unsolicited or bulk. I ignore most of them, but where it came from someone I know, it's not spam. Now, if Facebook (or some craptastic App) sends things to me that are not actually from a friend/contact/someone I know or does so by duping someone into sending the mail, then yes, that's spam. I guess it's kinda the definition of porn thing ...
Again, aren't we, as web app folks / eutrepeneurs /start-up peeps only talking about legitamate uses of sending email? I know I sure am and protecting my companies name / ability to send such mail and keep as much out of spam boxes and filters is of utmost importance. For folks who don't know much about the subject and want to know more, the OP is a good post to get rolling. Surely not the be all and end all though, but a good starting point.
With tens and hundreds of emails in the INBOX, going forward, how much would email contribute to the virality of the application? Can SMS work out to be an interesting alternative? SMS is guaranteed to be delivered, there is no SPAM filtering yet and the probability of reading SMS is much higher than an email.
I'd be unhappy to get random invites via whatever method. Whatever happened to word of mouth? Of people telling other people about a cool app/site off their own back, because they like it and it's useful to them?
This is just 'legitimized' spam IMHO.
If your product is that good, you don't have to "convince current users" to help you spam... If you make your product really well, people will market it for you, because they like it and want to tell their friends.