It seems that I have logins on 50-60 websites right now, and I rotate through a series of passwords depending on the importance/sensitivity of the site. For example, I might have a unique 12-20 character passphrase for each financial institution as well as a different second-level verification, but for relatively unimportant social networks I've signed into once or twice, I'm likely to share passwords.
All websites send me unwanted me at some point, which is frustrating but a reality of modern internet life. As a way to blacklist the most egregious violators, I've started creating custom aliases for each vendor site, and deleting those aliases when they spam me. A lot of the spam comes whenever a website adds a new feature they can email me on, giving me a new place to opt out.
There is no technical solution to solve spam, and there seems to be no way to convince new start-ups that no, just because I did them a favor to evaluate their website, they do not have the right to spam me. My solution is to delegate the management of all this noise to my virtual administrative assistant. At first this seemed like an easy task, then I realized I would have to personally change my passwords on all of these sites, since most of them have passwords I'm worried about other people knowing.
Trust delegation is certainly a solvable problem, and one new web-sites could easily implement early on. The most ideal solution would be an extension to OpenID which lets you delegate and revoke access to your accounts to another OpenID account. This way I could just assign my admin a task, "Update my bio and on all of these sites", or "upload this new photo as my default avatar on all of these sites", or even better, "Log into all of these websites and tell them to stop spamming me".
There, my need is out there. Get to it, I expect everybody to have this implemented by the end of the year.