In my 25+ years of instrument experience I have yet to see a
self-adhesive felt dot or rubber button that did not fail.  The
adhesive usually lets go over time, and the felt dot falls off.
Murphy's Law often comes into play and the now "foreign object"
ends up somewhere it shouldn't be, impeding the proper functioning
of something else.

Besides, as the link that Robbie offered shows, the felts are
usually made of acrylic or other material that is inferior for pianos.

The solution?  Buy or punch out your own punchings from good wool
felt and glue them on with a proper glue.  Hot hide glue and fish
glue are my favorites.

Best Wishes for 2007,
Jurgen Goering - Piano Forte Supply
www.pianofortesupply.com