Any chapter that tries to engage alumni back to the chapter should utilize a section of their website to alumni matters.
I work with Fraternity Management Group and virtually insist that separate websites are created for alumni (and parent) purposes. Each site will link to/fro the undergraduate sites, but are managed by myself or a chapter alum.
Here's an example:
http://www.gamma-rho.org
The value of sites like this have become overwhelmingly successful. I couldn't imagine managing alumni programming or even fundraising services without them.
Pete Parker
Reno, NV
Arizona Kappa Sig