Check if a website is revealing email addresses
You need to use the tools of the trade to check if your website is revealing emails from visitors or yourself. Most webmasters have a contact form somewhere on the page which sometimes reveales the real email address of the webmaster.
But even tricks like adding spaces to the email address, a REMOVEME part, writing (at) instead of @ and other means are recognizable by some email harvesters that do nothing else but to harvest websites and the websites that they link to for new email addresses.
One software that can crawl single pages, a website and even linked sites is 1st Email Address Spider. It costs $99 but everyone may freely test the software with some restrictions. It is nevertheless sufficient for quickly crawling your own website to find all instances of public emails on it.
Once installed you simply enter the url of the website or page that you want to check, select if outgoing links should be checked as well and enter login information if needed.
The tool connects to all webpages and links it can find afterwards and collects emails found on those pages. It's really interesting to see that websites advocating that you should conceal your email addresses are actually revealing lots of emails on theirs.
The best way to not give away your email address would be to not include it on any of your websites. Add a contact form instead that visitors can use to get in contact with you. If you have to publish an email address you should consider using an image, or more than one, to display it.
Some bots however are good enough to be able to process images as well.
Update:
One option that you have to run a quick check is to search on a site such as Google or Bing for @domain.ext. This reveals all email addresses that the search engine found. It should be clear that this is not necessarily a complete list but it is free and a fast option.
Another option is to run a search on the database -- if the website in question is database driven -- and all source files to find email address leaks this way.
Your post gave me an idea:
http://blog.donationcoder.com/index.php?item=1795
I stumbled upon an encoder for mailtos on websites that I used in my original design. It has seemed to do the trick for me!
http://hivelogic.com/enkoder