We're looking to move a bespoke intranet across to SharePoint. One query that has come up is whether we can do the following easily:

1. When user logs in for the first time they should be forced read and accept an Acceptable Use Policy for the site.
2. Agree a separate agreement that relates to their data being shared with other parties.
3. (Optional) upload their profile photo. They can skip this step if they don't have one but they should be prompted to do it each time they login subsequently.

The above is all nice and easy in a bespoke app but I can't see how to do this with SharePoint. Can we build a custom workflow that is tied to the user logging in? So far I can only find how to attach workflows to libraries and lists.