(A site operator here; the site was launched a few days ago. The idea is that anyone campaigning for a patent reform can use support by designated inventors as a presumably convincing argument in the eyes of the general public.)
Edit: As Richard Stallman points out in a comment at EFF's site, abolishing software patents can be easier than shortening the period during which a monopoly is granted to 5 years as EFF proposes; he cites a requirement by WTO that all patents are granted for a period of 20 years.
The nice thing about publicly supporting abolition is that you automatically support "less radical" proposal's like EFF's 5-year reform, and you support all of them at the same time just once and all campaigners can use your support. DRY :)