Michael Kassner recently posted on Tech Republic about "Trusted Web sites: Exploit tool of choice" based on the latest Websense Security Labs twice-yearly Web-based malware report (PDF): http://www.websense.com/site/docs/whitepapers/en/WSL_Q1_Q2_2009_FNL.PDF

There is always a fine line between being aware (and making others aware) of security threats and FUD; I think this is safely in the former.

• 233 percent growth in the number of malicious sites in the last six months (671 percent growth during the last year).
• 77 percent of Web sites with malicious code are legitimate sites that have been compromised.
• 95 percent of comments to blogs, chat rooms and message boards are spam or malicious.
• 57 percent of data-stealing attacks are conducted over the Web.
• 85 percent of all unwanted emails in circulation contained links to spam sites and/or malicious Web sites.

The last point is timely, and is also relevant to the idea of exploiting trust - in this case email from a known source.  I've just received an email from a family member (who shall remain name-less - for now):

• Subject: FW: Fw: Never, ever answer a cell phone while it is being RECHARGED!!
• Attachment: Mobile Phone recharge.pps (173 KB)

Hmmm - would you open this? 

Firstly, I would be exceedingly wary of stuff like this - why do people need to send this sort of thing in a PowerPoint?  (or at all?)  Any sort of complex file-type like this (Word, excel, etc) is simply a more capable platform for evil. 

Secondly, assuming from the file name that there is an eminent danger here, I would strongly urge you to validate that kind of thing; Snopes (http://www.snopes.com) is a good site for this.

For more general info see:
http://en.wikipedia.org/wiki/Urban_Legends_Reference_Pages

In the specific case of the phone recharging, see:
http://www.snopes.com/horrors/techno/cellcharge.asp

Lastly, I would suggest you make anyone who sends this sort of stuff out to you aware of these issues, prevention is always better than the cure.