<% %> in ASP.NET (embedded code blocks)

Question

I understand what these signify in the markup of the aspx pages ... but I don\'t not know the full power they can be used for or even the name to denote these special directives

Answer 1

Yes, those symbols indicate to the server parsing the page that the code within those tags should be interpreted as code and not HTML.

So, to answer your other question, you can use conditionals and most any other programming features supported by the server.

Check out a quick guide to ASP: http://www.w3schools.com/asp/default.asp