For linking to feature instances there is by default an anchor in the title of every feature instance so it is possible to view the source of the page and get the id for the anchor and then you can make a link to it. The anchor would look something like this:

<a id='module38' class='moduleanchor'></a>

and you could link to it with the page url plus the anchor like http://yoursite/somepage.aspx#module38

To link to a user profile you just visit the profile page of the user you want to link to and copy the url from the navigation bar and use it in a link.

Hope it helps,

Joe