Yes, if the data collected by the form/lead form is published in one way or another. Some scripts that people use to capture leads use a simple text file to store the details. If you know that they are using such a script, you can easily find their textfile with leads. It's published, the site owner just don't know or care.

If the data is available... then you can scrape it. If the data is in a private area, such as in a membership site, then the software can still scrape it if you have access to the site (username&password).

If you just want quick & dirty access to data, there are several queries you can type into google to find out what data is available.

Labno, if your idea is to grab information that people enter into someone else's web site, that's highly illegal and will almost certainly result in jail time if you're caught.

If you're asking about people entering information into your own web site, or a site belonging to your client, then it's trivial for a program running on their web site to gather the information that users entered into a Web form on the site.

Please clarify what you have in mind. If you're asking how to do illegal computer piracy then this thread should get deleted. If you don't know how to read form information on your own site, then you need a very beginner-level Web coding tutorial.

Yes it's possible to do that,

Does it involve exporting mail addresses from current storage of the addresses or is it just about collecting the addresses that are being entered from now on and forward?