The problem
In the SEO process you are submitting websites all the time. Sometimes to Search engines, sometimes to link exchange sites, to directories, to ping services, etc. There can be some paid services among them too.
Having a good sense about security you are using different passwords for all these web services of course. So in many cases it becomes a one-time stop just leaving your links to boost your PageRank.
Now the real problems start: The websites you joined start to sent you numerous newsletters, you forgot to uncheck that checkbox. Or another problem, the URL of your website changes or you want to resubmit your website.
Which Password did you use where?? Is your membership expired?? Maybe you have monthly payments for memberships you don't even use any more.
The idea
Of course you can buy or download a peace of software called a Password vault. This will help you remember your passwords, but is only a desktop solution. What we need is a web-enabled application so we can find our data wherever we are. Now this is a Great New Website Idea!
When ever you install software or join a website you insert a record which the specific data of that product in the online database.
What we need to know is:
1. Website / software name.
2. URL
3. Username.
4. Password.
5. Date joined.
6. Renew before.
7. End membership before.
8. Price.
9. Pay before.
10. Paying method.
11. Etc.
A site holding data like this must be trusted with a very high security level. Some of the measurements that must be taken:
1. Username / Password.
2. Encryption of data stored in the database.
3. SSL.
4. Strict separation of the various users.
Only a reliable partner could make a success of this.
Commercial opportunities
This is clearly a practical problem for many of us. With a good marketing strategy the designer of this site can make a living of it.