How secure is unauthorised PHP email and comments???

[savvy]

Hi, I'm at the design stages of design a portfolio site and am thinking of incorporating a PHP "email this link" function, so that users can email the page url to friend and maybe even include as short message.

My question is how secure is this function? can I expect for spammers to hack my site and abuse this function or am I being paranoid? I've noticed on some sites that allow anonymous commenting that they sometimes become populated by viagra adds and the usuall crap. I don't really want to include an image verification script, would it make any difference if the "email this link" function had a flash front-end?

Any advice or suggestions for further reading would be appreciated as i'm pretty new to PHP.

Cheers

[Weedpacket]

PHP's mail function is exactly as secure as mail. What matters is how well written your code is to use it.