Stock Manipulator, SEC Nemesis -- and 15 (2001)

If a department was to write a report based upon a position they held, or if a firms trading arm traded based upon a yet unpublished report that another department had written, then in both cases the firms would likely be breaking the law.

Financial firms normally have information registers, so if you have people from either side of the information barrier discuss a company then that has to be recorded and that information is used to restrict the actions of the individuals involved. Passing restricted information over the barrier without registering it can be enough to lose your licence even if the information isn't used improperly.

However if you hold a position in a company you are perfectly free to go and promote your view of that company as long as you declare you're own interest. You're not allowed to pump rumours and there are specific restrictions on projections, but you can perfectly freely talk about why you think a stock is worth buying.

Most Apple blogger are on safe grounds assuming they don't hold apple shares and aren't spreading the rumours for the purpose of moving the share price.

In general you are allowed to repeat rumours you believe to be true but you have to be very explicit that what you're repeating is a rumour.