astroturfing n.
The use of paid shills to create the impression of a popular
movement, through means like letters to newspapers from
soi-disant `concerned citizens', paid opinion pieces, and the
formation of grass-roots lobbying groups that are actually funded
by a PR group (astroturf is fake grass; hence the term). This
term became common among hackers after it came to light in early
1998 that Microsoft had attempted to use such tactics to
forestall the U.S. Department of Justice's antitrust action
against the company.
This backfired horribly, angering a number of state
attorneys-general enough to induce them to go public with plans
to join the Federal suit. It also set anybody defending Microsoft
on the net for the accusation "You're just astroturfing!".