Ms. Heller, 36, is CEO of the invitation-only social network, which began nine years ago as a site where fancy people could trade tips on art openings in London or samba nights in Reykjavik. ("Facebook for the few, " as Ms. Heller put it with a sigh.) An invitation to A Small World was once highly coveted, but the site's social currency has waned in the Twitter age.

WSJ: Q&A With A Small World CEO Sabine Heller | On the Road

But now knowledgeable amateurs and industry experts can trade stock tips for no charge in popular personal investing sites such as the Motley Fool.

ECONOMIST: Electronic commerce

Mr. Robinson blamed Mr. Kluger for pressuring him to trade on inside tips.

WSJ: The Confessions of an Inside Trader

The SEC said Lenowitz used the information to trade for the firm and his own accounts and continued to trade using the tips from Franklin after he left Chelsey Capital in 2003.

FORBES: Magazine Article

They continued to use the UBS analyst tips to trade, according to the SEC.

FORBES: Magazine Article

Trade newspaper Motorsport News tips Wrexham as a favourite place to base the race.

BBC: Wrexham interest in Wales Rally GB move from Cardiff

The tips allowed them to trade ahead of the announcements.

FORBES: Helter-Skelter On Wall Street

Using the Yellow Pages and the local trade association, Spinell has helped generate a list of prospects, and offers phone tips.

FORBES: All in the family

As part of National Consumer Protection Week, the Federal Trade Commission has organized a coalition of public- and private-sector organizations to provide practical tips on a wide range of topics.

WHITEHOUSE: THE WHITE HOUSE