Does Pop-Science involvement hurt one's reputation? There is a divide between the scientific community about involvement in popular science. I would define it as involvement in NatGeo/Discovery type documentaries, writing columns for newspapers/magazines, blogging about articles of popular nature (Like End of the World, Tsunami or whatever). 

Does involvement in such issues harm one's reputation in academia?

I have frequently seen grad students shy away from such opportunities because they think they will be made fun of or won't be taken seriously when they go and speak about "actual" research.

(Although I am talking about grad students, the scenario isn't very different for faculty as well IMO)

Some people like Stephen Hawking or Richard Wiseman have actually authored best selling books. Whereas a majority of people in academia stay in the confines of the journals.
If certain fields of academia do in fact frown upon "popularizing" science, then they are shooting themselves in the foot.

One of the most important ways of securing funding in different disciplines is through getting support by the federal governments in which they are working. Convincing politician X that you should fund research on doohickey X and widget Y to solve problem Z rather than funding their new shopping mall or football stadium requires convincing them that your research is important and worthwhile. The key to doing this is having a message to sell—something that the lobbyists and staff persons working for the government officials can take to them and say "this is what you need to know about why this is important."

An excellent way of doing this is to take part in writing columns, producing features for television, and other "popular" methods of outreach. You'll have to figure out how to distill your message in a way that's exciting for the viewer or reader, and that will help no only you but your peers as well.