At least in the case of contemporary, political matters:
If it is really true that "many people" in the contemporary mainstream believe something, it should not be hard to find a well-known public figure, or political columnist, or major-newspaper editorial writer, who expresses that belief.
For example, "some people regard the situation in Iraq as a guerrilla war" can be replaced with "Army Gen. John P. Abizaid said that forces in Iraq were 'conducting what I would describe as a classical guerrilla-type campaign against us.'"
The big problem with attributing a view to "some people" or "many people" is that it is an unverifiable source. (It's sometimes suggested that opinion polls be cited, but suitable poll results are generally hard to find. Polling organizations sell their services; you can't just go online and access the full results of every Harris/Interactive poll that's ever been conducted, search for relevant results, and snip out fair-use extracts).
Ideally the person cited should have more stature or neutrality than, Al Franken or Ann Coulter. But even the use of a Franken or Coulter IMHO fixes the problem. It establishes several things, fairly objectively. 1) the point of view is being expressed really in the contemporary mainstream (not just held by single-taxers or hollow-earthers). 2) The accuracy of the quotation/citation can be checked. 3) The reader either already has, or can easily form, an opinion about the source's point of view and reliability.
-- Daniel P. B. Smith, dpbsmith@world.std.com alternate: dpbsmith@alum.mit.edu "Elinor Goulding Smith's Great Big Messy Book" is now back in print! Sample chapter at http://world.std.com/~dpbsmith/messy.html Buy it at http://www.amazon.com/exec/obidos/ASIN/1403314063/