If you are making the SparkPeople Web Search page, www.sparkpeople.com/myspark/web_search.asp
your homepage, on the left side there is a link that says, "Click here to make this your homepage!" When you click on that link, there is a button for you to click to receive SparkPoints for making it your homepage.
For email points, you can only get points for the newsletter type emails. If you are receiving those, towards the bottom of each of those types of emails there is a button for you to click on to receive your point for that email.
The box for getting an email when someone replies to your topic should already be checked. If you are unchecking that box, you won't receive an email when someone replies, but if you leave it there, you should receive an email. If you have trouble receiving any of our emails, you may need to try the suggestions here for receiving our emails: www.sparkpeople.com/community/help_answer.
I hope that helps!