"A lobbyist is an activist usually paid by an interest group to promote their positions to legislatures. A lobbyist can also work to change public opinion through advertising campaigns or by influencing 'opinion leaders' or pundits, thereby creating a climate for the change his or her employer desires. The word lobbyist comes from the chambers in which the act of lobbying usually takes place, an anteroom near legislative bodies, for instance, or even the lobby of hotels where important people are staying. In American politics, most lobbyist organizations are headquartered on or near K Street in Washington DC, so "K Street" has become somewhat synonymous for lobbying. (emphasis mine)
It is very easy for a lobbyist to stray into bribery -- the most direct way to influence legislation, obviously, is to bribe enough law makers to ensure that the bill you support passes. Therefore, lobbying is heavily regulated. Of course, a lobbyist rarely makes the news unless he or she has transgressed the regulations, and as a result, 'lobbyist' has rather negative connotations these days. Measures to control the influence of lobbyists include campaign finance reforms, often promised but rarely passed. "(emphasis mine)
I never thought I would see activist and lobby at the same sentence but lobbying is heavily regulated is too funny. Clicking at the image or the link below is a glimpse of the reality:
Internal Memo Confirms Big Giveaways In White House Deal With Big Pharma