An e-Petition is an effort to collect signatures or questions via the web. The British government uses it a lot. So does the Scottish parliament and many local councils in the UK.

e-Petitions are also used by many NGOs, when they try to get as much support as possible for a special campaign or a special issue.

Some efforts have been made also to do Europe-wide e-Petitionsd. But so far without success.

See more:

The UK government's e-Petitions:

http://www.number10.gov.uk/output/Page297.asp  

The Scottish parliament uses e-Petitions a lot:

http://epetitions.scottish.parliament.uk/