It used to be that words like "portal," "infrastructure" or "content" would come up when the topic was an Internet public offering. These days, however, it seems you're just as likely to hear language such as "loyalty programs," "points," "awards" and "incentives."

That's because in the past few weeks we've seen an onslaught of IPOs from Internet-based direct marketing companies. The latest is Netcentives, which began trading Thursday under the Nasdaq symbol (NCNT).

Offering 6 million shares at $12 each, Netcentives saw its stock open at $13 1/2, straying as low as $12 1/4 and as high as $14 1/4 by early Thursday afternoon.

Unless something changes, Netcentives appears headed for an inauspicious debut. Which puts it in familiar company, for none of the recent IPOs from Internet direct marketing companies have been greeted warmly by investors, as the chart below shows:

Since their IPOs, all of these stocks have remained in close range of their first-day closing price.

Why the across-the-board antipathy among investors? Probably because they are having trouble distinguishing between the various players.

The basic business model for nearly all Internet direct marketing companies is similar - attract people with promises of free stuff, special offers or "points" toward a prize in exchange for their patronage or demographic information that is sold to participating companies looking for targeted marketing lists or e-commerce sales. And partner with high-traffic Web properties.

(Oh, don't forget to throw in a lot of exclamation points on your Web site. In fact, maybe we should refer to public offerings from Internet direct marketers as !Pos.)

Netcentives main program is the ClickRewards Network, which rewards consumers with frequent flyer miles when they buy stuff online through a participating company. Web sites that belong to the ClickReward Network include barnesandnoble.com (BNBN), E*TRADE (EGRP), macys.com, OfficeMax.com and Preview Travel (PTVL). Begun in March 1998, ClickRewards has more than 2 million members, according the Netcentives' S-1 filing.

Netcentives had only $647,000 in revenue in 1998, though in the first six months of this year revenue has jumped to $3 million. (Net loss also has increased from $14.1 million in '98 to $16.1 through Q2 this year.)

Those revenue figures are in line with the other companies listed above. At the top is Webstakes.com, with $4.8 million in '98 revenues, followed by opt-in e-mail player yesmail.com, with $4.6 million, and then FreeShop.com ($1.3 million), MyPoints.com ($1.3 million) and Cybergold ($1 million).

The company claims 10 million subscribers, and was the 14th most-popular Web property in August, attracting 9.1 million unique visitors. In contrast, MyPoints.com, the runner-up among Internet direct marketers, was ranked No. 36 with 4.1 million unique visitors. None of the others cracked the top 50.

Investors recognized Xoom.com's superior positioning when the company went public on Dec. 9. Offered at $14 per share, XMCM stock opened at $31 and closed even higher at $34 7/16, a 146% first-day gain. Since then Xoom.com has traded as high as $98 =, and was selling Thursday afternoon at $59 3/4.

With a $1.1 billion market capitalization, Xoom.com is valued at anywhere from three to five times more than its half-dozen competitors listed above, making it the direct marketer to beat for now.