My concern is whether you see this as a real "startup" or a side project that can bring in a few bucks. How are you intending to bring in revenues? Monthly/Annual fees? Ads? The problem I have with both of these models is that when I look back over the past year, only once would I need to use your service, when I left my job to start a company. Looking forward outside of an occasional title/profile or a rare move I'd use this very infrequently. Not enough by far to do a membership or drive significant ad revenues.
> [how do we plan to make money]
You're right that people won't need this every day, but even if you only need it once every 2-3 months, it's likely to be worth it--consider how much time is required to notify all your service providers of new information, then multiply that by your hourly rate. Needing it every 2-4 months is also not implausible: the individual changes (credit card expiration, email address, postal address, job title, etc) are infrequent, but when you stack them up they become relatively common.
Add in the fact that we provide a better interface than many of the services we are updating (e.g. PayPal and Yahoo, which disperse your information across multiple pages and show different versions of it in different places; e.g. some pages show title (Mr), some show suffix (Jr), some show middle name/initial, etc), and suddenly a modest fee starts to seem ok.
Our plan is to have a "one day" plan for very cheap--probably about $2--that is useful for a one-time use. When you're done, you can either have us delete all your data or archive it so that there is no charge until the next time you need it...but there will be a moderate charge to reactivate it. Alternatively, you can pay a small monthly or annual fee. In the long-term, we would prefer to negotiate contracts with the service providers and have them pay us to provide this service so it could be free to the users, but we will need a significant user base before we can make that happen.