Activation on site
<p>I have been running my website for a few months now and occasionally I find my activation isnt great. After the user signs up, they will receive an email which has an activation link provided. </p>

<p>I have a few problems and want to improve this if possible.
Firstly, the email sometimes doesnt arrive? Any reason for this?
How can I stop it going into the junk mail?</p>

<p>Secondly, at the moment, the activation is their username and an md5 of their username.
Is there a better way to do activations?</p>

<p>I'm always looking to improve and find better ways of doing things!
Thanks for your time.</p>
